2c^O!'F5

FISHERIES RESEARCH BOARD OF CANADA AstiCI '[ iV'F-;S

Translation Series No. 2813

The biology of reproduction of pinnipedia of the

by M. M. Sleptsov

Original.Title: Biologii razmnozheniya lastonogikh dalbnegb vostoka.

From: Zoologicheskii Zhurnal (Zoological Journal), 22(2).: 109-128, 1943.

Translated by Ian MacLaren

Department-of the Environment Fishèries Research Board of Canadà. Office of the Editor Ottawa, Ontario..

1973

21 pages typescript JOURNAL OF ZOOLOGY Vol. XXII 1943 No. 2

The biology of reproduction of pinnipedia of the Far East

M. M. Sleptsov

Laboratory of evolutional morphology of the vertebrae, Moscow State University.

The present paper is the result of a study of pinnipedia during a hunting expedition, organized in 1939 by the Institute of the Fishing Industry in the Pacific (TINRO). The author participated in the expedition on board the hunting vessel "Nazhim", which operated in the Okhotsk and the Tchukotsk between May llth and Oct. 20th 1939. During the expedition the author investigated the reproductive systems of the males and females of the Erignathus barbatus naut. Pall., the Phoca vitulina largha, Pall., the Histriophoca fasciata Zimm, the Phoca hispida Schreb., Eumetopias jubatus Schreb., and the Odobeanus rosmarus div. Illiger. The results of the investigations of the reproductive systems of the above mentioned pinnipedia brought out many interesting and important details, which complemented the problems of the reproduction of pinnipedia in general, and those of the Far East in particular. Because of the intensity of the seal hunting industry, the knowledge of their biological reproduction gains primary importance since it is only under such circumstances that a rational planning of the catch can take • place. Regardless of the importance of the problem, it had not been studied intensively up to this time; the rhythm of reproduction of various types of pinnipedia has not been determined as yet. There are pertinent re- ferences in the literature on the reproduction of the pinnipedia, but such references are not complete and have not been checked in every case. It would appear that such types of pinnipedia as the Greenland and the Caspian seal have been studied fully, since they are the object of an intensive industry. Work in that respecthas been done by Smirnoff (1935, 37), Freiman (1939), Gerasimoff (1931), Naumoff (1933), Dorofeyeff (1936). Regretably, a whole series of problems of the reproduction of pinnipedia have not been solved as yet. The biology of reproduction of the Phoca bai, is known only on the basis of fragmentary data by Swatosh (1925), Witkowski (1890) and Naumoff. The data on the seal populations of the White, the Barenz and the Karsk Seas are even more scanty. The study of the reproduction of the pinnipedia of the Far Eastern has been concentrated mainly qan the Otaridae and Eumetopii. There are some data on Odobaeni and Phocidae, but all very scanty; (Barabash-Nikiforoff 1936; Freiman 1936 ;Naumoff 1933 ;Ogneff 1935; Dorofeveff 1936 ; Loon 1936; Nikulin 1937; Pikhareff 1939). -2-

As the result of the study of the biology of reproduçtion of the pinnipedia, the whelping time has been investigated fairly thouroughly. The questions of coupling, the gestation time, barreness, the intensity of reproduction etc., require furthersupplementary studies. For example, the majority of authors assume that with Phocidae the gestation lasts about 11 - 11.5 months. However, Ogneff (1935) pointed out that with Phoca vitulina the gestation lasts only 9 months.

OWN OBSERVATIONS TABLÉ 1 No. Total Specie m f During the whole period of Erig. barb....433 213 220 the expedition we studied the re- Phoca vit.1...188. 74 114 productive systems of 657 males and Hisp ..... 722 females. General data about Sch...... 478 184 294 the material used are presented.in Histrioph. tables 1, 2, and 3. fasc. Zimn...:280 186 94 Total ...... 1379 657 722 Over the period of time the numbers of animals were distributed in thè following manner, according to type.

TABLE 2 Total. Total. Months S ecie. No. m f Months Specie No. Erig.barb ..... 10 3 7 Erig.b...... 128 72 56 Ph.vit.1 ...... - - - Ph.vit.l... 11 2 9 May hisp.Sch.... 61 28 33 Jul. hisp.Sch. 77 31 46 Histrioph. Histrioph. fasc ...... 129 97 32 fasc ...... 5 1 4

Erig.barb.:..109 - 64 45 Aug. No catch Ph.vit.l...... 16 6 10 June "hisp.Sch....350 125' 215 Erig.b.... 127.' 39 88 Histrioph., Sept. Ph.vit.l.. . 90 28 62 fasc...... 146 90 56 Oct: Erig.b.... 59 20 .39 Ph.vit.l.. 71 49. 30

According to age and sex the grouping was the following.

Table 3 , , Sex f. Not sex. f., Sex. f. Potent. Not. sex.f, Specie mat. m. tiat. m. mat. f. sex. f.mat.f. sex.f mat.i

Erig:b ...... 164 49 160 26 34 Ph.vit.largha...... 56 18, 86 19 9 "hisp.Schreb...... 121. 63 187 44 63 Histrioph. Fasc. Zimm158' 28 85 10 9

The zoological length of the animals was measured, and the reproductive systeins of males and females were examined under field conditions.

-3-

Male testicles and sperm ducts were examined. The testicles were weighed and then measured wit a centimeter tape. The condition of the utc.ri, evaries, atria and the _:ervices of uteri were examined. A limited number of ovaries of specirons of all four types and in differtnt stages o1 development, were we;he ,.:.. The general conditions of the animals were also noted: the stage t log reached, whether well fed or not etc. We shall now describe the conditions of the reprductive systems both male and female, of pinnipedia of the different types, caught during the different months of the expedition.

ERIGNATHUS BARBATUS NAUTICUS PALL.

Data on condition of the reproductive system.

7 sex. mature males and 7 sex. mature females were ekamined in May. Table no. 4 indicates the weight of the testicles. There was no sperm.in the ducts; the • TABLE 4 testicles were compact and swollen. Length of Size of test. Weight animal 3 The reproductive system cm cm of the females has been found as follows; the uterus was . 246 5* x 8 59 of normal proportions. Its 205 • 4 x 8 . 60 colouring approaches the ' 220 6 x 9 68 colour of the flesh. The surface of both horns is covered with considerable folds, which probably , originated after the Shrinking These horns are . asymmetrical; _in some cases • the right horn, is bigger:than the left, in others the proportions are re- versed. The internal walls of the uterus show signs Of past parti; approximately in the middle of one of the hornsof the utexus we-found - -a considerable belt- shaped thickening of the mucous lining, protruding into the lumen of thé uterus. The ovaries showed resorbent corporae lutiae of pregnancy(Fig:. The colouring of the mentioned thickening is brownish, because of the presence of thick, enlarged veins and arteries.

140ii

`IA Yerri Fig. 1.. Longitudal section from above, throiigh:. the.horn of the utérus of Erignathus barb:. m.s.- muscles; mucous:lin.;:k.s - blood veààels vatz.- oviduct; 'va. - ovary; zh.t. - - resorIping corp,11: of pregnancy: fOl. - small •folliculi; r..foL • -• résorbing cross section of »vary. -3-

Male testicles and sperm ducts were examined. The testicles were weighed and then measured with a centimeter tape. The condition of the uteri, ovaries, atria and the cervices of uteri were examined. A limited number of ovaries of specimens of all four types and in different stages of development, were weighed. The general conditions of the animals were also noted: the stage of moulting reached, whether wéll fed or not etc. We shall now describe the conditions of the reproductive systems both male and female, of pinnipedia of the different types, caught during the different months of the expedition.

ERIGNATHUS BARBATUS NAUTICUS PALL.

Data on condition of the reproductive system.

7 sex. mature males and 7 sex. mature females were examined in May. Table no. 4 indicates the weight of the testicles. There was no sperm in the ducts; the TABLE 4 testicles were compact and swollen. Length of Size of test. , Weight animal 3 The reproductive system cm cm of the females has been found as follows; the uterus was 246 5 x 8 59 of normal proportions. Its 205 4 x 8 60 colouring approaches the 220 6 x 9 68 colour of the flesh. The surface of both horns is covered with considerable folds, which probably originated after the shrinking. These horns are asymmetrical; in some cases the right horn is bigger than the left, in others the proportions are re- versed. The internal walls of the uterus show signs of past parti; approximately in the middle of one of the horns of the uterus we found a considerable belt- shaped thickening of the mucous lining, protruding into the lumen of the uterus. The ovaries showed resorbent corporae lutiae of pregnancy (Fig. 1). The colouring of the mentioned thickening is brownish, because of the presence of thick, enlarged veins and arteries.- Al/ MRS

ifors

Z11.1, Yerz Fig. 1. Longitudal section from above, through the horn of the uterus of Erignathus barb. m.s. - muscles; s-.s. - mucous lin.; k.s - blood vessels vatz.- oviduct; va. - ovary; zh.t. - resorbing corp.l. of pregnancy: fol. - small folliculi; r.fol. - resorbing fol; Below: cross - section of ovary. -4-

The thickening of the mucous lining is the locus of past placentation (placenta uterus). The cervix of the uterus is weakened, its colouring reddish, with bluish patches. The vagina is normal. There is no milk in the milk glands. The ovaries are asymmetric and flabby; they are light mauve in colour. The corpora lutia, which show through, are of dirty orange or yellowish hue. When the ovaries were opened, they dis- closed one, and somethimes two, large growing corpora lutia, and also corpora lutia in the process of resorbtion. There were no signs of pregnancy; we have obviously observed active ovulation in these ovaries. All specimens were in active moulting stagé. Males and females were caught during the last days of May (22nd till 30th), in the area of the Iona Island in the Okhotsk Sea. In June we have examined 64 males and 45 females, of which 42 were sex. fully mature, while the remaining 22 were not. The criteria for the determination of maturity were the following characteristics : the presence of sperm in the ducts, and the size and weight.of testicles. The size3of testicles (without the epidermis of mature specimens averaged 40-60 cm , and weighed 45-75 gr: The^testicles of not sex. fully mature males were-,. much smaller,'and weighed less. They averaged 5-35 cm3 and 5-40 gr. Between June lst and 31st the testicles of mature males were compact and swollen. Sperm was discovered in the ducts. It is interesting that not in one single case could we find either fully sperm filled ducts or epididimis. We could only observe small quantities of sperm. This should not be taken as an indication that coupling has either not taken place or has passed already. It is most probable that there is not much ejaculation. in the ducts of Erignathus barb., and the Phocidae in general, during coitus. The reproductive system of sexually fully mature females showed every indication of ovulation at its peak. We have found in the ovaries one, and sometimes two, large folliculi, 1.2 - 2 cm in diameter, besides one or1some- times two corpora lutia of ovulation. In.some cases the corpora lutia have been found in the right as well as in the left ovary. In the mucous lining of the uterus we observed a zonal thickening of pinkish or reddish cblouring. (Fig. 2). The zonal thickening of the lining is arranged in the following way: outside the zone of reddening, the mucous lining of the horn of the uterus is of an uniform, pale pink hue. Closer towards the middle of the horn the .mucous lining grows considerably thicker so that the upper semi-circle joins the lower (Fig.2). This joining of the zonal thickening of the mucous lining results in a cavity, where-the thickening of the mucous lining encloses a spacé within the horn of the uterus. The described thickening is equipped, in a contrast with the surrounding mucous lining, with a,thick network of blood vessels. The horms of the uterus, whiçh have the ring-shaped thickening can.be easily observed even without the incision of the horn, since the outside walls of the horn are swollen; (Fig. 3). In these dilations of the mucous lining we found embryos in early stages of development (Fig.4). Obvioùsly, the appearance of.the ring-shaped thickening of the mucous lining signifies the onset of pregnancy. As this dilatiôn is accompaniéd by the appearancè of thecorpora lûtiâ in the ovaries, the pregnancy can be diagnôsed even under absence of.a visible embryo.

1 corpora lutia of ovulation (om.in transl.) !ebb

.Fig. 2. Lonfitudal section from above, through the horn of the uterus of a fem. Erign. barb., at the onset of pregnancy. The ring-shaped joining together is shown (s.s.), and the formation of the cavity (p), separated from the rest of the lumen of the horn of the uterus (p.r.) Below, a cross-section of the ovary in the early stages of pregnancy.

In the first days of June (3/6), we discovered an embryo in the cavity of the thickening of the mucous lining. The embryo was most likely, in the gastrula stage of development. The embryo was situated between the folds of the lining of the uterus; its coadunation with the lining of the uterus had just commenced. We regret that we could not preserve the specimen described above. We found another example of the similar embryonic development on July 14th (Fig.5). In the second half of June we frequently found embryos in the early stakes of development, measuring from 4-5 to 10 mm. (Fig. 6 and 7) In July we hunted in the Academy Bay and in the Shantar Sea. 72 males and 56 females were studied. There were 63 sexually fully mature males, and 42 females; 8 potentially sexually mature and 6 not sexually mature. Ovulation was at its peak in the ovaries of sexually fully mature females. We found frequently pregnant females with embryos in the early stages of development; (embryos ranged from 4-5 to 22 mm). Moulting of sexually mature animals was coming to its end, and many animals had shed their coats completely. On July 3rd, in the Academy Bay, we happened to observe actual copulation of Erignathus barbatus. We observed 2 animals playing in water 'about 10-15 m away from the killer boat (Fangsbot), moored to an ice floe. After some time they paired, in such a manner that the head of one animal came above the head of the other; the second animal's head barely touched the chin of the first animal. For some time both animals remained perpendicular to the water level, but then separated under splashing. Afterwards, both animals swam away some 40-50 m, and hauled out onto an ice floe, one after the other. The male came out last, recognisable as such by the visible penis erectus. •They continued to play on the floe. The male then pushed the female into the water, and the animals paired again. 1 Our observations coincide fully with those made by Pali. "Coupling takes place in water....with the animals in perpendicular position, showing only the heads..." I

In.July we observed ejaculate in the ducts of,the males, light blue in colour, 'the testicles compact and swollen. On July 14th, in the Bay of Academy, we found an embryo in the uterus of a sexually fully mature female; the stage of development of the embryo was difficult to ascertain. Most likely it must have been in the gastrula stage of development (viz fig. 5). There was no catch in August; hence we could not gather any data. In September we examined 88 females and 39-males. 40 females were pregnant, 30 barren, 10 not sexually fully mature,.and 8 potentially sexually mature. There were 27 sexually fully mature males, and 12 not sexually mature. The.testicles of the sexually mature males proved to be flabby, deflated and much Fig.3. The dilated walls of the ^►^ uterus of a female Erignâthus barb., smaller in dimension than in May, during the period of*iiidden pregnancy, June or July. We.could not or in the early stages of development discover.any traces of sperm in the of the embryo'. male ducts. The ovaries of the pregnant females showed large corpara lutia of pregnancy (up to 1.5 - 2 cm). In addition, the ovaries containedresorbent corpora lutia, which apparently were the corpora lutia of ovulation, formed earlier. There were no large folliculi. Embryos measured 18-30 cm (Table 5). The ovaries of potentially sexually mature females disclosed growing corpora lutia of ovulation and large folliculi. In October we examined 20 males and 9 females.2 The testicles,of the sexually fully mature males shrunk even more by that time. All females were sexually mature; we found 26 prégnant and 4 barren ones. Embryos measured from 18-32 cm. The expedition ended on November 20th, and therefore our work had to be discontinued. •

COUPLING

As already stated above, a coitus of Erignathus barb.had been observed on 3/7, and the first embryo in the early stages of development was found on 3/6; on 14/7 an embryo was found estimated to have reached.the,gastrula stage of development. During the second half of June and the first half of July we frequently found embryos in the early stages of development..

1. Published by K.K. Chapski . 2. In actual fact, we examined more animals, but since no measurments were made,- these were not included in the analysis. The conditions of their reproductive org. were taken into consideration. Apart from the obvious symptoms of preg- nancy (presence of visible embryos in the uterus), we often met in June and July specimens, in whose uterus and ovaries we were able to discover symptoms of not visible pregnancy. This not visible pregnancy is characterised by the presence in the uterus of the already described zonal thick- ening of the mucous lining of the uterus, and by the presence of the corpora lutia of pregnancy in the ovaries. In some cases the zonal diletion were not as yet fully closed at the time of observation, and the lumen of Fig. 4. Longitudinal section the uterus was still free; in other cases of the uterus of Erignathus the zonal thickening was already closed. barb. Inside the ring- Inside the cavity, made by the edges of the shaped dilation of the mu- mucous lining, when these close together, cous membrane one can observe the (viz fig. 2), we sometimes found serous embryo (amnion and chorion fluid. We have observed the described facts have been removed). during active ovulation; we also found sperm ducts of the males at the same time; coupling was also taking place and in the uteri we found embryos in the early stages of development. Hence we can conclude, on the basis of the mentioned facts, that Erignathus barb. does not have any lengthy latent period (of 2-2.5 months), since in June and July we did observe coupling while finding. visible embryos (even if in gas- trula stage), and signs of not visible pregnancy; and later on (in September and October), we found more or less uniformly developed embryos (in relation to the spread-out whelping time). We then can state that with Erignathus barb. the latent period does not last more than two weeks. To provide a more defined presentation of the time when coupling commences, we bring the sized of embryos of Erignathus barb. in our table no.5. As it can be observed, we have collected data on the most early embryonic stages. Up till now such stages have not been found in June or July. We shall attempt to estimate, at least approximately the ages of the embryos. In the already quoted work of K.K. Chapski we find the following statement: "In spite of the fact that we have examined a large number of Erignathus barb., we did not find amongst them any signs of pregnancy before August. August 12th (1930) is the earliest date at which we have observed a visible embryo. Next year, the first pregnant female was discovered on August 22nd. The embryos of both females were approximately same in size; they reached 17&22 mm, measured from their occipital protruberance to the tip of the body; they weighed 1.6 and 2 gr, inclusive the covering membrane. The age of these embryos did not exceed 4-6 weeks, according to the estimates of professor S.I. Lebedkin. In the first case, therefore, the development of the embryo started, probably, not earlier than the first days of July; in the second case, not earlier than the middle of the month." (p.40). The sizes of embryos collected by us were, in the majority of cases, much smaller than those collected by Chapski, and their age was, approx. twice as low. In some cases it did not exceed 1 - 2 weeks. The fact that we secured an embryo In the gastrula stage, supports the contention that we were collecting materials during the peak period of coupling and the onset of pregnancy. Chapski's as- sumption about the existence of a lengthy latent period in the development of a -8-

Table

Size of Location Condit. Date animal of hunt of pelts

17/6 197. Bay of Fin. moulting 25/ 212 Sakhalin It It 26/ 190 26/ 190 ^., 26/ 200 1/7 216 Bay of 2/ 186 . Academy. 3/ 217 3/ 209 3/ 227

200 Slight,^y moulting

3/ 219 Fin. moulting 3/ 204 Slightly "

3/ 205 .. . 3/ 212 Fin. moulting 3/ 216 t t . .fi 17/ 205 Bay of 17/ 194 Ulban

8/ 200 8/ 220 Bay of Academy

8/. 210 8/ 216 8/ 201 9/7 202 , Shantar 9/ 205 Sea . 9/ 219 10/ 201 10/ .216

10/ 205 . 10/ . 216 10/ .211 . 12/ 193 it . . It , 12/ 200 12/ 213 if - , if . . . 13/ . 286 . 14/ 217 Bay of IT 14/ 232 . Academy Just finishing moulting

14/ 241 Fin.-moulting 14/ 195 II 14/ 215 i f 14/ 196 it

fertilised ovum is not likely, since his main support of the theory was based on the assump- tion that coupling could hardly take place during the period of moulting. Our findings prove the contrary: coupling does take place towards the end of the moulting • • period and thereafter. Hence we 0 ' can state with certainty that coupling of Erignathus barb. takes place in June and July. We regret to say that we could not obtain much material in May, and therefore it is difficult to say any- thing definite about this time period. Fig. 5. Embryo of Erignathus barb., We can assume that coupling may take gastrula (?) diam. lmm. place even towards the end of May. The peak, however, is reached during the time from the second half of June until the second half in July and peters out towards the end of that month. We are certain that no coitus takes place later than July, and we are confirmed in our opinion by the dimensions of the embryos encountered during the autumn; In the majority of cases they are of the same age (allowing, of course, for the individual differences in the time of pairing). Table 6 gives us the sizes of embryos of Erignathus barb., encountered during September and October (for brevity's sake we did not include all cases.) We did not find any small embryos (up to 10 cm.). Our data on the absence of pairing of Erignathus barb. during the autumn coincide with those of Chapski.

Table 6

1 Size of Size of S ize of Size of Date anim. cm embryo cm Date anim. cm embryo cm

17/9 233 18 11/10 - 28 17/ 212 22 11/ 30 17/ 200 16 11/ - 29 17/ 202 19 11/ 25 23/ 235 24 11/ 31 23/ 215 25 11/ - 24 23/ 210 22 11/ - 28 23/ 194 23 11/ -. 25 28/ 222 27 11/ - 23 28/ 220 25

1-FemaleS. were not measured -10-

t

Fig. 6. Embryo of Erigna- Fig. 7. Embryo of Erignathus thus bàrb., 7mm. barb., llmm.

WHELPING

We do not have any data on whelping of Erignathus bârb., in the Okhotsk Sea. Scanty references in.literature on this subject indicate that whelping takes place in March - April (Okhotsk Sea ârea) and in the Tarter Straits apparently as early as February (Naumoff) Nikulin states that a pup of Erignathus barb. was caught on Match 16th.

DURATION OF GESTATION.

Therefore, if coupling of Erignathus barb. takes place towards the end ' of'May, in June and July (with the;peak period during the,second half.of June and the first half of July), and whelping inFebruâry, March,and April, we must concludethat"gestation lasts 9 months.. We coincidé in"our firidings with Chapski, who determined the actual duration of gestation as being 9 months, for the Karsk and the.Barenz Seas. They do not coincide, however, with hisas- sumptions about the latent period; on this basis he estimated the over-all gestation period at 11 months.

BARRENESS

While inspecting the reproductive systems of sexually fully mature females in June and Jthly, we fqund that some.females showed no signs ofembryos, although the pairing period was at its peak. We must point out thatbecause of the, circumstances, it was difficult to arrive atany.conclusions about the barreness offemàles, since we did not,knowwhether a given female would have been fertilised or-not. Only in the autumn were we able to arrive; at concrete con-• clusions about the barreness of.the females. By;that time the period of coupling was over, and when we encountered sexually fully.mature females who did not exhibit any signs of fert3izàtion, we could establish this bythe.size of the .animals and by 'the conditions of uteri and the ovaries, we could"then fully determine their barreness. We bring here a series of examples. On September 17th 1939 we caught 240 animals on their hauling out place on the island of Sivoutchi Kamen in the Shanter Sea. We examined 125 specimens. The distribution of sexes was as follows : 66 males, 69 females; 48 out of 69 females were pregnant, 18 barren, 3 potentially sexually mature and 2 not mature. On

September 18th we caught 6 animals off . the Birds Island (Shantar Sea); 4 males and 2 females; 1 female pregnant, the other barren. On September 21st we caught 117 animals on the northern island of Sivoutchi Kamen. On one hauling out place we caught 48 animals: 20 males and 28 females. On the second hauling out place we caught 52 animals, 27 males and 25 females., Of the females from the first hauling out place there were: Pregnant 8 Barren 6 Pot. sexually mat 8 Not mature 6 Of the second hauling out place: Pregnant 12 Barren = = 5 Pot. sexually mat = = 4 Not mature = = 4 On Sèptember 23rd we caught 10 animals on the Utich Island: = 1 male and 9 females (3 pregnant, 5 barren and 1 not Mature.) On October llth, on the same island we caught 78 animals: 33 males and 45 females (22 pregnant, 15 barren, potentially not sexually mature 2). In this way we obtained the following data for the autumn: 92 pregnant females (51.5%); 50 barren (30%); 21 potentially sexually mature (10%), and 15 not mature (8.5%). As it can be seen, 30% (adj.) of the not mature, whelping females remain barren. On the basis =of these facts we can draw the following conclusions: sexually mature, whelping females, (that is, generally capable of whelping) do not whelp every year. Those females who have whelped this year, remain evidently barren until the next year, i.e. whelping comes every other year. We can, however, observe that the percentage of pregnant females is considerably higher than the percentage of the barren females. We believe that the apparent discrepancy can be explained in the following manner. The 51% of pregnant females include those who have paired =this year for the first time. The presented percentual relation of pregnant to barren females has been based on the small numbers of the counted catch, and should not be considered from the general point of view of the reproductive capacity of the population. We want to emphasise only the fact that whelping with this specie des not occur every year. According to= our data the relation of males to females of Erignathus is 1:1.

COMMENCEMENT OFSEXUAL MATUREITY.

We have only indirect data on the commencement of sexual maturity with Erignathus barb. We encountered individual yearlings during the= spring and the= summer months, measuring 135-150 cm. In the autumn we registered yearlings of 140-165 cm. We have no data on the size of the newly born pinnipedia in the Okhotsk Sea, and it is difficult to draw any conclusions on the rate of their growth = during the period of milk-feeding. We can assume that the length of a newly born Erignathus barb. varies between 110-140 cm. It is, however, quite possible that the newly born specimens are considerably smaller. S.V. Dorofeveff (1936), writing about the rate of growth during the milk-feeding period of the Greenland seal states that: ' During the period of milk-feeding the offspring grows about 25% of its original length (from 91 to 115 cm). "(p.35) We shall assume that a newly born Erignathus barb. measures 120 cm; he reaches approximately 150 cm after the milk-feeding period and then his rate of growth diminishes. The yearlings reach 150-165 cm in the autumn. According to our observations, the one year old specimens measure 170-185 cm, two years old some 185-190 cm and three years old 190-200 cm. During the summer and the autumn periods the pregnant females measure between 186 cm and 240 cm. (viz table 5 and 6.) On the basis of the above we are inclined to believe that the sexual maturity of females is reached after their 3rd year. Female 185-190 cm long (2 year olds) belong to the potentially sexually mature group. However, in tables 5 and 6 we find that females of this size have been impregnated. We can therefore assume that we are encountering here the usual deviations of sizes; it is also possible that some females reach the stage of sexualy maturity at the end of their second year. As regards the males, our findings indicate that they reach sexual maturity after their 3rd year. The size and the weight of the testicles of the 195-200 cm group correspond to those of sexually fully mature animals. We shall touch briefly on the organisation of the sealing industry. The present planned dates of hunting are, in our olbinion, not rational. Erignathus barb. is hunted from April 15th to july 20th on the ice floes of the Okhotsk

• Sea, in the area of the Iona Island, in the Bayoof Sakhalin and in the Shanter Sea. Then there is a period of rest, and Erignathus barb. is hunted again on the autumn hauling-out places in the Shantar Archipelago from the beginning of September till the second half of October. From the economic and utilitarian point of view, the hunting should be more restricted. It would be more rational to hunt after the whelping season, and before the coupling commences, i.e. from April until June 15th. Autumn hunts on the hauling-out places of the Shantar Archipelago should be stopped altogether, because it results in the killing off of pregnant females. Besides, the animals are constantly being disturbed by . the hunters. In 1939 the hunters visited the hauling-out places practically every second day. Undoubtedly, these frequent visits distrub the general physiolo- gical tempo of the animals. The resting periods of the animals are interrupted, and in the females wounded with sticks there occurs a resorbtion of embryos. If it is imperative to continue with the autumn coastal hunting new hauling- out places should be looked for. This would prove useful in the rotation of the hunting places.

PHOCA VITULINA LARGHA PALL.

In Jime we exeMined 6 sexually mature males, 8 not sexually Mature and 2 potentially sexually mature females. The testicles of maes were compact and swollen.. Their size reached 35,32,37,30,35 and 4o cm ,a.nd the weight was 56,52,50,52,60 and 48 gr. The ducts and the epididimiP showed the presence of ejaculate. . The reproductive system of the sexually fully mature females was found - to be in the following condition; thé uterus was normal in dimensions, the horns, as well as the ovaries, - were asYmmetrical. -Traces of past parti were ,disdovered in.three females;'belt-shaped dilations of the mucous lining of the-uterus'of 'dark red hue and wrinkles on the horns. However, the ovaries showed - large folliculi and,corpra lutia of ovulation. There were no signs of impregnation. -13-

In July we inspected 2 sexually mature males and 9 sexually mature females. The uteri disclosed large folliculi, up to 1.5 cm and corpora lutia. in diameter

COUPLING.

Early stages of pregnancy were observed for the first time on July 14th. The hunters and the staff member of TINRO, com.P11chareff brought in 5 uteri of the Ph.vit.l. (no measurements made). Upon incision, one uterus revealed an embryo of 6-7mm in length, which had reached the stage of development of three brain vesicles and as yet open nerve cords of the caudal part. The finding of the embryo on_July 14th, active ovulation and the presence of the sperm in the.ducts of the males can be taken.as indicative of the beginning of coupling. it starts in June, continues through July and, perhaps, until the middle of August. But the peak of.this period is reached, undoubtedly, at the end of July. G.A. Pikhareff (1930) writ'es on this matter; "Although considerable time has passed since the whelping season, no females showed any signs of embryos. In.July I found large folliculi in the uteri of only a few females." He then continues to describe how, (mid. of Aug) he observed the coupling of Ph.vit.l. in water. In September and October, while hunting on the autumn hauling-out places, we succeeded in bringing in the following material concerning the Ph.vit.l. Almost 100% of the sexually,f.ully mature, whel:ping females were pregnant. The sizes of embryos in September.did riot exceed 23 cm, and in December some 35'cm.. We could observe diminishing ovulation in the ovaries of the potentially sexually mature.specimens (resorbtion_of the corpora.lutia of ovulation and regression of fôlliculi.). In separaté:cases ovulation was still taking place. . The testicles of the sexually fully mature males in September and October were in a state of recession..and smallér.in size.thân in May, June and July, We found no presence of ejaculation. All the stated facts indicate that no pairing of the Ph.vit.l. takes place in.the autumn; this contention is sup- ported by.the sizes of the embryos (table 7)...

Table 7

Size of Size of Size of Date Anim. cm. Size of embr.cm., Date :. . anim.cm. embr.cm. 15/9 156 '16 . 14/10 162 155 28 18 .165 .160 25 17 157 145 . 24 .15 165 25 21/ 172 20 155 26 18. 170 30 - 22 160 24 4/10 . - 24 - 20 _ 23, 25 19 19/10 28 171 . 25 ^ 30 14/10 178 24 - 173. 26 27 24 160 . 22 - 23 25" = 21:_ "Our data on the sizes of embryos of Ph.vit.l. do not correspond with the data gathered for the same'imonths by Stakhanoff .(viz Ogneff's_data above). -14-

The following information was given by G.A. Pikhareff in 1938 about the sizes of the embryos of Ph.vit. 1. during the months of the autumn: "..on September 3rd we found embryos of 7-11 cm; on September 6th 4-5 cm; on September 9th 1 cm; on September 10th 2 cm; on September 14th 7, - 12, 15 cm; on September 25th the embryos found were 11, 12, 18, 22 and 26 cm. In Octobér we encountered the following embryos: on October 4th one specimen measuring 11•cm; on October 16th, 13 and 21 cm." The embryos of 1, 2, 4, and 5 cm have been measured wrongly, as we found out during a talk with Pikhareff. He measured them length-wise, from the tip'of the head to the protruding point of the curled in tail (along a straight line from the head downwards, over the stomach to the bend in the tail.) After we have checked the difference, we established that the sizes as shown by Pikhareff (1, 2, 4 and 5 cm) should read 3,.5,_7 and 8 cm. The sizes of the embryos encountered'during the first part of September fully confirm our data on the protracted period of coupling of the Ph.vit.l. If the coupling of the Ph.vit.l would take place in March or April, or even in May, as assumed by Freiman (March), Barabash-Nikiforoff (at the end of May based on the observations of the local inhabitants), then the embryos we would find in June or July-would undoubtedly measure more than 2-3 cm.. This we have not found to be so. Ph.vit,1. does not pair in the autumn.

WHELPING.

According to dates. to be found in the pertinent literature, the whelping of the Ph.vit.1 takes place in March and April (Freiman, Dorofeveff), in April and May (Barabash-Nikiforoff), towards the end of February according to Nikulin and at the,beginning of winter (Smirnoff). Ogneff reports that in the By of Sakhalin the Ph.vit.l. whelp in February, March and evèn at the beginning of April, while S.P. Naumoff observed whelping in the Tartar Straits_ and the Bay of Peter the Great in March and in the middle of April.

DURATION OF GESTATION.

. Therefore, pairing of the PYi.vit;l. in.thè Bay of Sakhalin of the Okhotsk Sea takes place in June and July. However, according to the existing literature the whelping in'that area has been.observed in February, March and the first half of April. Using.these data one can easily estimatè the duration of the gestation. Speçimens wheiping in February.probably paired.towards the end of May.. Those whelping in'Marckjaud many authors'give this date) paired in June, and tti6ie vhelping in April coupled in'3uly.< The gestation .then; with,t^e Ph.vit.l. '$oc+'!? 'i!dt last 11. months, as many authors assumed,- but only 9 months,

BARRENESS.

During the autumn,hunt.all-sexually fully.mature and capable of whelping females (100 specimens) were pregnant. There were only.4 females in that group with the embryos in the process of resorb.tion: This.makes us assume that Ph.vit.l. whélp yearly. There are the following details on onset of sexual maturity in male.'and female Ph.vit.l.. . The size of sexually not mature females,ranges from 96-139 cm while the size of potentially sexually mature females rèaches 140-145 cm.. The size of sexually fùlly mature, whelping females and-ôf pregnant specimens ranges from 145 cm upwards. In the autumn (September. October) the yearlings of thé:Ph..vit.l. reach 107-115 çni. If we consider that newly born Ph.vit.l. do not exceed 80-90 cm, 1. Gestation with the Eurmpean Phoca vit, which is closely related to the Far Eastern Ph.vit.l., also lasts 9 mQnths, as stated by S.I. Ogneff. -15-

it means then that in 6-7 months after being born, they grow 25-30 cm in length.. One year old specimens reach 125-130 cm, and two years old some 135-145 cm. As females of 96-139 cm are obviously young, which can be also determined by the underdeveloped uteri andby the absence of any signs of ovulation in the ovaries, one can assume that specimens of 96-115 cm are yearlings, and those of 120-139 cm are one year old. Females of 140-145 cm can be generally classed as potentially sexually mature; their ovaries exhibit signs'of ov- ulation, and the size of their uteri approaches the size of the uteri of sexually fully mature females. On the basis of the above facts we can as- sume that the female Ph.vit.l. are able to begin reproduction after their second year. For practical purposes all females of 2.5 - 3 years can be considered as sexually fully mature. We can say the same about the males; they reach sexual maturity after their third year. According to our data and to the data supplied by the journals of TIHRO, the relation of sexes is 1 ; 1.

PHOCA HISP IDA SCHREB.

We only have extensive material for May, June and July. During the autumn hunts we met only few of the specie, mainly not yet sexually fully mature specimens. In May we observed in all females signs of past parti. The uteri of the females who had whelped exhibited dilations of the mucous lining (Pl. uterus), of dark red hue, and there were traces of resorbed corpora lutia of pregnancy in the overies. We did not find any barren females. We discovered signs of ovulation only in the second half of June and the first half in July. Sperm in the ducts of the males was observed in the first half of July fér the first time. We did not encounter any impregnated females during the whole time, in spite of the fact that we examined more than 200 sexually fully mature specimens. On Jely- 14th we discovered an embryo, most probably in the gastrula stage of development (fig.8). During the autumn hunt in October we caught only one pregnant female. We could not examine her, but according to the hunters the embryo hardly measured 10 cm. In 1938, on September 25th, a pregnant female had been brought in, the embryo measuring some 5 cm. Since we did not have sufficient material for the second half of July and the whole of August, we cannot state anything specific about the onset of coupling of Ph.hisp. During that time we had not succeeded in discovering any traces of hidden pregnancy, as described in the case of Erignathus barb., except the one case of July 14th, or any traces of visible embryos. We can be only sure that coupling must take place in the second part of July and during August, not as soon after the whelping and the period of lactation as •many scientists have hitherto assumed, but conàiderably later. If Ph.hisp. - whelps in February, March, April and even in the first part of May (acc. to Dorofeveff), and pairing takes place undoubtedly

1. i.e. sexually fully mature females (omis. in transi.) Fig. 8. Enbryo of Ph.h ispida Schreb., gastrula()., diam. 0.5 mm. towards the end of July and in August, the gestation then lasts some 8 months, and not 11 months. The data at our disposal let us arrive at the conclusion that the details of reproduction of the Ph.hisp. are similar to those of Ph.bai. According to Dybowski and Godlewski, this specie stars their drive in the middle of July, continuing until August. According to Swatosh, the pairing of the Ph. baicalensis takes place in June, after the ice breaks up into separate floes. It takes place in water. These observations are supported by the sizes of embryos. In August these reach 70-130 mm, in September 226 mm. Whelping takes place in February - March (acc. to S.P. Naumoff). So that if the coupling of the Ph.bai. takes place in June-July, and whelping in February, the duration of gestation is 8 months. We could not discover any visible embryos in Ph.hisp. during the first half of July. At that time, the animals still kept to the ice floes (there was still ice in the Bay of Academy and in the Shantar Sea.) During the second half of July the ice had been broken up by storms, and began to melt. The captain of the hunting ship "Nazhim", A.S. Solyanik, and also the staff member of the TINRO, G.A. Pikhareff, tà1d us that in July 1938, on their way from the Shantar Sea to Sakhalin, they met considerable herds of Ph.Hisp., obviously headed for the Amur estuary. Undoubtedly, coupling of the Ph.hisp., as in the case of Ph.bai., takes place in water, and starts in the second half of July and continues throughout August, particularly then, when the animals gather in herds. Our suppositions about the onset of pairing are fully supported by the sizes of embryos found in October , and September. In October they measured some 50 mm, and in September - 100 mm. The gathered material permits a more or less close estimate about the onset of sexual maturity with Ph.hisp. We examined some 478 males and females; this 'number includes both, the sexually fully mature and not mature specimens. We encountered yearlings in May, June, July, September and October. At that time, these measured some 50-65 cm, in spring as well as in summer, and 65-75 cm in the autumn. The reproductive systems of both males and females was emphatically juvénile. The next group uf males and females measured 75-85 (mn. The conditions of the reproductive systems were those of young, not yet sexually mature animals. This group consists obviously of one ,year olds. The third group included specimens of 85-95 cm, about one year and a half to two years old. The reproductive system,of femalesof this group was characterised by enlarged uteri and ovarieS. Ovulation could be observed. Besides, in few individual cases, members of this group showed traces of past parti in the uteri, (in females of 93-95 cm.) Finally.there was the group of obviously sexually fully mature animals of 95-135 cm. 'Ali males and females were sexually fully mature. We can assume that the onset of sexual maturity in males and females comes after the second year. Journals, kept over a period of years, show that the distribution of females to males is 60% to 40%. We must take'into consideration that the main part of observations was gathered in one area only, namely the Bay of Sakhalin. We consider that there are more females in that area, because they are caught soon after whelping. The females of Ph.hisp. whelp in this area. If the Ph.hisp. were hunted in autumn, the distribution of sexes would probably be more equal. We are inclined to think that the relation is 1:1. -17-

HISTRIOPHOCA FASCIATA ZIMM.

We obtained data on this specie between May 14th and July 14th. Besides, we made use of the journals of V.A. Arseneff, who participated in the expedition of TINRO from the end of April until the second half of July. During that time we have inspected some 200 sexually fully mature females and more than 300 sexually mature males. The reproductive system of 100 sexually mature females was examined. In May and the beginning of June we could observe that the ovaries and the uteri returned to their usual size (after the whelping). The horns of the uterus are slightly asymmetrical, the folds of the horns are straightened out, and the ovaries disclose resorbent corpora lutia of pregnancy. At the end of June and the beginning of July we observed active• ovulation in the ovaries of all sexually mature females. We could discern large folliculi (up to 2 cm in diameter), and large corpora lutia of ovulation inside the ovaries, more than 1.5 cm in diameter. The testicles of sexually mature males reach their largest proportions and the greatest weight; their size ranges from 35-50 cm and their weight from 40-80 gr. According to all data, the coupling was supposed to commence in the second part of July; since the expedition terminated on July 14, we could not observe the beginning of pregnancy. It is true that on July 14th , in the Bay of Academy, we encountered an embryo inthe early stages of development, in a sexually mature female. The size and the degree of development require histological investigation. We can only state that together with the chorion it measured 4 mm in diameter (fig.9.). On the basis of the factual material about the conditions of the re- productive system of the males and females, we can state that the pairing of Histrioph.fasc.Zimm. does not •take place in March, April or May, i.e. shortly after the whelping, as it has been assumed before; but, on the contrary, it takes place after a considerable time has elapsed since whelping, and after moulting. Ac- cording to our and Arseneff's - Fig. 9. Embryo of Histrio- servations the moulting of the Hist- • phoca fasc.Zimm., gastrula, mm rioph.fasc.Zimm. ends generally, du- in diameter. • ring the first half of June, i.e. before the coupling commences. The date of the finding of the embryo in the early gastrula stage of development,(July 14th) permits us to place the onset of coupling as sometime in the beginning of July. Such an estimate can be only a very rough one. If the whelping of Histrloph. fasc.Zimm. takes place in March, April and even in the first half of May , then it is selfevident that the gestation laats 9 months.

• The staff worker of TINRO, V.A. Arseneff did not observe whelping of the'Histrioph, fasc.Zimm. in May, but onlY Crests?) -18-.

We cannot say.anything definite about the onset of the sexual maturity and barreness. We do not possess sufficient material_(i.e. the majority of pregnant females were in different stages of pregnancy), and the col- lections of ovaries, uteri and testicles have not been, as yet, evaluated histologically. In the nearest time we shall endeavour to publish the findings of our collections. The distribution of population is 1 1 (we utilised the materials gathered in 1938 by Pikhareff, and by Arseneff and ourselves in 1939).

SOME OBSERVATIONS ON EUMETOPIAS JUBATUS SCHR., AND ODOBAENUS ROSMARUS-DIV. ILLIGER.

In addition to the observations on the reproduction of the Phocidae of the Okhotsk Sea, we should mention some facts on Eumetopii and Odobaeni. On May 14th.1939 two Eumetopii were caught on the edge of the ice off the eastern coâst of Sakhalin. One was male of 315 cm,.the other'a pregnànt female of 246 cm. The embryo was taken out and examined. Its body.was covered withshort, thiclç fur, mouse grey in colour. The size of this offspring, a female, was 94 cm. The embryo was located in the left horn of the uterus, its head towards the exit. The ovaries of the.pregnant female were examined, measured and, weighed. They were extremely asymmetrical: the left measured 6 x 5 cm, and weighed 37 gr; the right one measured 3 x 4 cm, and weighed 7 gr. The left ovary disclosed a large and compact copror lutius of pregnancy 4 cm in diameter. The right ovary lacked both, the corpora lutia and large folliculi. . The right testicle measured 11 x 6 cm, wèighing 97 gr; the left testicle 11.5 x 6.5 cm, and weighed 107 gr. On May 19th, near the Cape of Elisabeth (North Sakhalin),twô more Eumetopii were caught; a male of 345'cm, and a pregnant female of 234'cm.. .The embryo proved to be a male, measuring 105 cm. It was located in the left horn,of the,uterus, with its head.towards the exit: As.in the,first case, the ovaries were asymmetrical:. the left one measured 4 x 4.5 -cm; weighing 15 gr. We'found-a large corpor lutius (3.5 cm in diameter).inside the left ovary. The right one was void of corpora lutia and folliculi., The testicles of the embryo measured 1.5x 4 cm, and weighed 3.5 gr. The testicles.of the bull.measured 6 x 10 cm, weighing 40 gr._ Thère was-no sperm to be found in either the outlets or the ducts of the epididimis of both males. The ship "Nazhim" went on a walrus hunt in the Chukhotsk Sea, in-Aug. 1939. The animal was hunted in the area of Cape_Dezhneff and Cape_Serdtze-_Kamen, some 40-50 miles off the coast. During the 6 days of hunting, the ship took in the capacity load of pelts and lubber (170-t, 380 animals).. There were found large hauling-ou t places of males in thatarea, populated exclusively by sexually mature'.males '(3.5-4'.5 m). Therewere.very few Young males. 4 females were caught on solitary ice floes.dutside the area of the hauling-out place, (2.75, 2.70, 2.60 and 2.85). -19-

All females were in their lactation period and had sucklings measuring 130 cm. Both, the uteri and the ovaries of all females were examined. The dimensions of the uteri were normal, but the mucous lining showed traces of past parti: the zonal dilation (Pl. uterus), and in the ovaries we discovered (in 2 cases in the left ovary, in 1 case in the right ovary) corpora lutia of pregnancy in the stage of resorbtion. It is interesting that in other ovaries, connected with the horns of the uterus and free of embryos, we observed ovulation. _Besides, we should point out that in the female Odobaenus each horn of the uterus has a separate cervix of the uterus, i.e. the right and the left horns are completely separated from each other. This characteristic makes the uterus of the female Odobaenus differ strongly from the uteri of other pinnipedia.

CONCLUSIONS.

On the basis of the new facts in the biology of the reproduction of Phocidae of the Okhotsk Sea, as presented in this paper, we should bring in the data existing already in the • literature and pertaining to the biology of reproduction of Phocidae in general, and those of the Far East, particular. We shall examine first of all the already available data on • coupling of the Greenland, Caspian, Baikal and the Far Eastern Phocidae. Various authors have pointed out that coupling takes place after the lactation period and also during that period. However, these data are not based on the actual observation of the coitus, or a collection of embryos of corresponding stages of development, where the age could be determined on • the basis of their size, and the stage of development reached. Most of the writers are satisfied with observations of the behaviour of the animais: the beginning of coupling on the basis however„it is difficult to estimate of behaviour alone. It is quite possible that animais (especially the males) ' begin to exhibit characteristics of the period of heat during the time of whelping and lactation, which does not mean that the females are ready for mating. In this connection we should mention the following; all female Phocidae bear comparatively large offspring . • Both horns of the uterus participate; one contains the embryo, while the other holds a part of the allantoic sack. The mucous lining of both horns carries in itself all the changes connected with the gestation. The lining of the uteri and the ovaries resume their normal shape after 1.5-2 months after whelping. This has been born out by our observations of Phocidae in the Okhotsk Sea. Such pinnipedia like the sea- bears probably go through a different process. The embryo is located, together with the allantoic sack, in one horn throughout the gestation period, leaving the other horn free. As it is known, the female whales pair 3-4 days after calving. This is possible because one of the horns does not participate at all in the gestation and therefore its lining and the corresponding ovary are

ready to conceive. • Therefore, if there is no autonomy of the horns during the gestation, coupling does not take place shortly after whelping; if there is an autonomy of the horns, coupling then o akes place shortly after the whelping. We think that the problems of pairinethe Greenland, Caspian, Baical, and the Karsk Phocidae should be investigated more closely. It would be interesting -20-

to establish whether the coitus takes place in water or on a firm substrate. According to our findings, the coupling of Erignathus barb. and Ph.vit.l. takes place in water. A series of authors state the same regards to Phocidae, but some (Naumoff, Dorofeveff and others) consider that coupling takes place on ice or on the beach. The problem of either the presence or the absence of a latent period in the Eûropean, Baical and the Caspian Phocidae,.is also of interest.• Some are inclined to think that the presence of a latent period has been established with Phocidae. This assumption rests on the fact that.zoologists have never been able to find examples of early stages of embryological-development, aftér the assumed"on set of coupling of the pinnipedia. . According toour findings, the latent period is absent in the Okhotsk Phocidae. It would be interesting to.find out what influènces this development, if the European, and also'the Caspian siibspeciae of Phocidae exhibit the presence of such a period. Finally, as.the last question, there is.ttie problem of the duration of gestation with the.Phocidae." The majority of authors estimate the duration at 11-11.5 months.. According to our findirigs the duràtion of gestation with the Phôcidae of the Okhotsk Sea is only 9.months;.withthe exception of the, Ph.hisp., where the.géstation lasts 8 mônths.' It would-be also interesting to discover..the.cause for a shôrter duration of gestation in one specie, and a more protracted one in others. Why is it that with the Creenland and the Caspian Phocidae thé gestation lasts.ll months, while .the Histriophoca Zimm., which specie is`closely related, in the opinion of many scientists to the first mentioned.specie, has a gestation period of only 9 months. Perhaps the gestation in all Phocidae is of equal duzattdn and only various iricomple"te obsdrvations make one arrive at different conclusions.

DEDUCTIONS

As the result of this study.in the biology of the reproduction of Phocidae of the Okhotsk Sea, conducted tiy the expedition of..TINRO, on board theséal.ing vessel "Nazhim'',,from May 14th until October_20th 1939, the author arrived at,the following deductions: .

ERIGNATHUS BARBATUS NAUTICUS PALL.

1. Coupling.takes place,aftér the moulting, or towards the end of that period, in June and July. The peak is reached in the second'halfof June and the first half (if July.

2. Gestation làsts 9.months. . .

3. Whelping does not take place every year; the females, having whelpéd in.a given year.remâin barren until.the next year.

4. Sexual maturity of males and females is reached in 2.5 -.3 years.

5. Relation of^sexes is.1 : 1. 11( -21-

PHOCA VITULINA LARGHA PALL.

1. Coupling - towards the end of June, in July and the firat‘ half of August (the peak is reached in July.)-

2. Gestation lasts 9 months.

3. Yearly whelping.

4. Sexual maturity is reached after 2.5 - 3 years.

5. Sexes are in relation of 1 : 1.

PHOCA HISPIDA SCHREB.

1. Coupling commences in July - Angust.

2. Gestation lasts 8 months.

3. Yearly whelping.

4. Sexes are in relation of 1 : 1.

5. Sex. maturity is reached after 2 years.

HISTRIOPHOCA FASCIATA ZIMM.

L, Coupling takes place at'the beginning ofJune and July, and Probably :at the beginning.of August. :

2. Gestation lasts 9 months,'

à. Relation'of sexes is I.: 1.,

4, The rythM of.yhelping' has not been established.

1. Barabash-'-Nikiforoff, The Pinnipedia of the • Comandor Islands. Tr., VNIR0', III, 1936, 2. Vi•kowski, Observations'on. the .Problems of Phoca • B,aicaleneis. >Journal of the Earàt.Dept. and the Geogr. Society XXI-, No 3, 1890.

: Gerasimoff,• M.K. , • The llunting of 'the Greenland Seal. - V*adivostok 1931. Derofeveff, S.V. : , Meterial on thé Industrial BiOlogy, of Pinnipedia Dnring- the ,':Spring.-iée Period,.in• .the Tartar, Streits.. - 0011.,.: of VIKIRO,- III 1936, 'Dotofeireft , .S.V., Observations on..,,the period. of Re- production of the Greenland Seel. • • ; DM,USSR,'II (llth)No 187) 1936 ,DOrofeVeff,: S S., Meterier'On: the PUP PeriOd the .1,,ife.'et the ..GreenjulLncl. Seal The Aret Corn 31st cd 1936 •.'• •by4c.4,.e. for Zoologieel,'Gee,' SraphY'.of Eastern •'• • Journal of the Sib'.i!ept -.- and the -Geogr.:. Soc. III, No 2, 1872 - • '• Loon, .S . , Pinnipedia ..Of :Western, 4mtchatka. • III, •1936.`. ' •. • - 'NeuMoff, S.P., Phocidae of the U.S.S..R. ;. • Mcieçow •••• Leningrad 1933. P.G. Observetions of Pinnipedia of the OichOtek an&the Japanese ..Seas.

. The - Animals of the U.S.S.R: and the Adj,eining, ,CoUntrieS.• - . - , • • •• III,. State. Biol. Med. 1935. Pikharef f, G.A. gin tr4.opini!Ce-:,Faaciate.,. Jour. DVFAN, No 33 (1) 1939 Bel.ea*:. and ,its...Henting.

Sairnoff, NA., Investigations of the Hunting. Of -thé' ,.;., White Sea Sea1 -, . The'Nevest Observations On the White ,Seit Seal • Jour. of thé• Dept •V1. Leningrad: 1927'.. —' • • noff, .M.A.,.See Animale of the .Seee.-(Pinnipedia and Cetacea.) GUMP. ,, 1935.. . • 4>: Dorofelietti: S.V. ," The Caspian Seal • and the .Henting of 'it . Ori the Ice Floes, • No. - 3, 1928 . 1Freiman, S U., Materials. for the Industritil Biology of Par Biitatern. Pinnipéctia. VNI.R.0, .114.1936., • ; Fienteri,...s.u.,:Migrationsief•the Greenland Seal. • Journ of .Àdv. Knipowitch :liciaçotiir 1939., Chaptikt , KiK. , Erignethus :barbatuEi of :the'ICarak and :;.the - Bareni Seas'. ats Biology and ,ite Hunti:ngy Inst.. 123,, 1938,..i