THE MOLLUSCA OF LAKE ALBERT NYAN2A. Bv M. CONNOLLY.
(Read before the Soiie-ty. M ay yth, The only compreliensivc work on ilie fresh water ninllu?ca of Lake Albert Nyanza is that of E. A. Smilli' who recorded from it in i 8 8 S the following fifteen species, of which five were sii|iposed lo l>e new to science:—PUvwrhii sndaiiictis Mts. and staiiltyi AniMillaiin w tnui Phil,, Pahidina unicolor Oliv. (var.), Cleol'aira tmini Sniilh. Bythitiia alhtrli and waHeri Smith, Mtlanhx lul'tradnta Miill. and Hricinctn Smith, Unio irgyptiaius Caill., cnUIauJi I'er, and acuminatus H. Adams, Corbicuui nidiala and /'usilla l’hih|>pi. Since that date von Martens’ and Oennain“ have jiulili.shed slij;ht emendations of Smith's list and Cox' has broken entirely fresh ground of the most absorbing interest by describing a collection of fossils, of which at least five are new to science, made by 10. J. Wayland at Kaiso, near the eastern shore of the lake ; while, sub seqnent to tiie reading of the present paper, there has a]ipe:ired the magnificent work of Pilsbry and I!equa;rt' on the aquatic Mollusca of the Jielgian Congo, in which will be fonnd full geograjihical refer ences to all the recent species known to have been collected in Lake Albert. It might therefore seem that anything further on this snbject would be superfluous at the present juncture, but as a matter of fact, durnig the last three years Mr. and Mrs. A. O, Kisher and Captain C. R. S. Pitman have sent home collections which add to this fauna several fresh inhabitants, in addition to increasing our knowledge of the older, so that the following paper may be acceptable as a sequel to Smith’s earlier work. It will be noted that two of his original fifteen species have to be eliminated from the present list, while only nine of the remainder retain the names under which he listed them. As none of the fossils have so far been identified as still living in the lake, I propose to deal with the two sections separately. Nc refer ences to literature are given unless they have some important bearing on the present study. I include in the body of my list all species which have rightly or wrongly been recorded from the lake, and have adopted without question, save in one or two cases, the nomenclature employed by Pilsbry and Bequasrt.
I P.Z.S., 1888, pp. sa-56. s Deutscb O&t Africa, iv, 1897, pp. 3S9-3g4. 3 Arcb. Zool. Kxpdr., iv, 1907, pp. 134-127 and Voy. Bali.iiili, 1930, pp. 59-55. 4 Tbe Geology and Palnontology of the Kaiso Buiie-Beds (Government Press, Uganda 1926, pp. S3-7»). 5 Bull. Amer. Mus. N a t Hist., liii, 1927. (a) RECENT SPECIES. Family PI.ANORBID.®. Genus Planorbis Geoff. Planorbis sudanicus Mts. 18 7 0 Planorbis sudanUus Mts., Mai. Blalt., xvii, p. 3 5 . 18 8 8 do do do. Smith, P.Z.S., p. 5 5 . 1897 do do var. major, Mts., U.O.A., iv, p. 1 46. 1927 do do tanganikanus Bgl., P. & B., Bull. Amcr. Mus. N.H., liil, p. 122. Hab. Lake Albert (Emin ; Baker); Toro District, South shore of lake (Fisher); Ndandaraira (Pitman). Judging from such specimens as I have seen, I am inclined to agree with the nomenclature adopted above by Pilsbry and Bequasrt. Planorbis e:ibbonsi Nels. 18 7 8 Planorbis gibbomi Nels., Q. J. of C., i, p. 3 7 9 ; pi. iv, f. 3 . 1897 do do do Mts., D.O.A,, iv, p. 1 50. 1927 do {Gyraulus) do do P. & B., Bull. Amer. Mus. N.H., liii, p. 1 2 6 . Hal). Lake Albert, Kassenje (Stuhlmann); Toro Dist. (Fisher). Originally described from Zanzibar, there has long existed a little doubt about this species, owing to the figure not agreeing with the description; having recently examined specimens from Zanzibar, presumably topotypes, I can confirm their agreement with the form which is now universally accepted under the above name, and which is so widely diffused from Abyssinia to Cape Town. Planorbis adowensis Bgt. 187 9 Planorbis adowensis Bgt., Descr. div. Moll. &c., p. 11. 1897 do do do Mts., P.O.A., iv, p. 147. Hab. Lake Albert. Ndandamira ; Butiaba (Pitman). In recording this species from Lake Albert, von Martens rather doubtfully placed Plan, stanleyi Smith in its synonymy, and I think that he had in view examples of Smith’s species, rather than that of Bourguignat. It is probably due to this record that Germain listed adowensis, omitting all mention of stanleyi, and that P. and B. follow the synonymy suggested by von Martens, but it is doubtful whether the true adowensis has previously been recorded from the lake. The collections now under review contain two forms of a rather small shell of the sudanicus group; in one, the aperture remains about the same altitude as the last whorl, so that the shell is comparatively low, while in the other the aperture expands rapidly, so that the shell increases rapidly in altitude, this being the typical stanleyi Smith. In CONNOl.LV : THE MOl.J.USCA OF I.AKR ALBERT NYAN2 A. >?3 order to elucidate the question of synonymy, I submitted some ex amples of each form to Dr. Germain, who kindly reported on the former as follows:—“ The six examjiles of a form less tliick (less in altitude) belong to the forma minor of Plam>rHs adowtnsis IJjjt. However, in East Africa the two species ” {admvouii and the form sent him as stanttyi), “ present allied forms, more or less intermediate and often easy to mistake.” Planorbis stanleyi Smith. (=bridouxianus Bgt.)
June, 1888 Planorbis stanlfyi P.Z.S., p. 3 5 . Nov., do do hriJouxianus ligt., Icon. Mai. Tanganika, pi. I, f 9 -12. Hab. Lake Albert (Emin); Kassenje (Schubotz); Toro District (Fisher); Biitiaba ; Ndandamira (Pitman). Germain’s report is as follows:—“ The four specimens named Planorbis stanleyi Smith are very certainly Planorbis bridouxi liourgt. 1 have compared them with the type ol J. R. K., which is here, and there can be no doubt about the matter. If your specimens are really PI. stanleyi, the two species are evidently synonyms.” The type of stanleyi being in the British Museum, there can be no question as to the correct identification of the species, and that bridouxianus Bgt. must fall into its synonymy ; but whether it is really specifically distinct from adowensis appears a little doubtful, although the typical forms are easily distinguishable. It is worth placing on record that an immature example of this species, collected by Mrs. Fisher in the Torero District, on the north shore of Lake Victoria Nyanza, has similar apertural dentition to that of Plan. aUxandrinus etc., but I have failed to find this peculiarity in a large number of other young shells that I have examined. P lanorbis ch u d eau i Germ. (?)
1907 Planorbis chudeaui Gsrm., Bull. Mus. Paris, p. 2 7 4 ; text figure *3- Hab. Lake .Mbert. Ndandamira (Pitman). In his description of this species Germain states that its last whorl presents two very pronounced angulosities, one above and the other at the base, which give to it in profile a very sharp rectangular appear ance. Pitman’s specimens are extremely small, hardly a third as large as Germain’s type, and do not agree in all respects with other details of his figure and description, but they may be very immature, and as they present the extraordinary feature stressed by him of the double angulation, I do not venture to separate them from his species unless further material may prove them distinct. The circumference of the last whorl, in profile, is practically flat between the two rectangular carinae, from which points it inclines inwards towards the apex and base. Genus BuUnus Miill. (=Isidora Ehrn.) Bulinus strigosus (Mts.) 1897 Jsidera slrigosa Mts., D.O.A., iv, p. 1 3 9 ; pi. vi, f. 11. Hab. I^ake Albert. Butiaba (Pitman). The first record of this genus from Lake Albert Family P I L I D ^ . Genus Pila Bolten. Pila stuhlmanni (Mts.) 18 8 8 A m pullaria wernei VhW., Smith, P.Z.S., p. 5 3 . 1897 do erythroitoma Rve., var. stuhlmanni Mis., D.O.A., iv, P- 155 1927 Pila stuhlmanni Mts., P. & B., Bull. Amer. Mus. N.H., liii, p. 182 Hab. I^ke Albert (Baker, two young shells); Kasscnje (Stuhl- mann); Butiaba; Ndandamira (Pitman). All the specimens 1 have seen appear to be conspecific, and I follow Pilsbry in their designation; the largest shell collected by Pitman measures 9 6 x 8 4 mm. in its last ly i whorls, the earlier being deficient. Family V IV IPA R ID ^. Genus Viviparus Moiitf. Viviparus rubicundus (Mts.). 187 9 Paludina rubicunda Mts., Sitz.-Ber. Ges. Nat. Fr., Berlin, p. 104 18 8 8 • do unicolor Oliv., van, Smith, P.Z.S., p. 5 3 . 1897 Vivipara rubicunda Mts., D.O.A., iv, p. 1 7 9 . Hab. Lake Albert (Baker; Emin ; Gordon); Kassenje (Schubotz); Toro District (Fisher) ; Butiaba; Ndandamira (Pitman). Remarkable for its very rounded whorls, but very variable in form and colour, which may be red, brown, green or yellow. Family A M N ICO LIU ^. Genus Bulimus Scop. (=Bithynia Leach). Bulimus alberti (Smith). 188 8 Bythinia Smith, P.Z.S., p. 5 4 . Hab. Lake Albert (Emin); Kassenje (Emin and Stuhlmann); Toro Dist. (Fisher); Butiaba; Ndandamira (Pitman). CONNOLLV ; THR MOl.I.tJSCA OK I AKK AIHKRT NVAN7.A, I75 Bulimus tilhoi (Germ.). 1912 Bythinia tilhoi Gzxm., Hull. Afus. Paris, xviii, p. 3 2 2 . 1 9 1 6 do do do Doc. Sci. Miss. Tillio, iii, p. 3 0 6 ; pi i, f. 5-6. Hab. Lake Alliert. Toro Dist. (Fisher); I!utial>a ; Ndandamira (Pitman). A much smaller form than alberti or wallcri, agrei-iii" well witli Germain’s description of Hlhoi, which was originally described from Bengu, Niger Territory. Bulimus walleri (Smith). 1S88 Bythinid ?<«//<»■/Smith, P.Z.S., pp. 5 4 , 5 5 , f. 3 . Hal). Lake Albert (Emin); Toro Dist. (Kisher); Butiaba ; Ndanda mira (Pitman). Founded on a single specimen, which is not in the British Museum, it is satisfactory to have re-established this species, which is easily recognisable from Smith's figure. Examples of the typical form, collected by Pitman, are rather more mature than the type, exceeding it by nearly a millimetre in altitude, while a few still longer specunen.s, with much exserted spire, deep suture and very convex whorls, approach very closely the figure of B. martreti (Germain), (L’Afr, Centrale Franij;., 1 9 0 7 , pi. v, f. la). Family THIARID^E. Genus Melanoides Oliv. Melanoides tuberculatus (Miill.). 1774 Nerita tuberculata Miill., Verm,, ii, p. 1 9 1 . Hab. Lake Albert (Emin); Kassenje (Stuhlmann); Toro District (Fisher); Butiaba; Ndandamira (Pitman). 1 refrain from giving further references to this well known species ; the race inhabiting Lake Albert is an extremely small and slender one.
Genus Potadoma Swains. Potadoma liricincta (Smith). 1S8 S Metania liricincta Smith, P.Z.S., pp. 52 , 5 3 , f. t. 1897 do do do Mts., D.O.A., iv, p. 1 9 5 . 1917 Potadoma do do P. & B. Bull. Amer. Mus. N.H., liii, p. 2 8 0 , Described as from Lake Albert (Emin), but von Martens states that he was unable to find this species in the material collected in the lake by Emin and Stuhlmann, *hile Pilsbry and Bequasrt suggest that the type was picked up some distance to the west or south-west of the lake, and can be removed from its fauna. Potadoma tornata (Mts.). 1892 Melania tornata Mts., Sitz.-Ber. Ges. Nat. Fr,, Berlin, p. i 8 i. Germain includes this species in his 192 0 list for Lake Albert, but I can find no record of its having been collected there, the localities in which it occurs all appearing to be considerably to the westward. Genus Cleopatra Trosch. Cleopatra pirothi Jiclc. (=emini Smith). 1881 Cleopatra firolhi ]\ck., Jahrb. D. Mai. Ges., p. 3 3 8 . 188 8 do ««/«/Smith, P.Z.S., p. 5 4 , f. 2. 1 897 do Jick., Smith), Mts., D.O. A., iv, p. 1 85. Hab. Lake Albert (Emin); Kassenje (Stuhlmann); Toro Dist. (Fisher); Butiaba ; Ndandamira (I’itman). The representation includes varieties with one, two or three Carina;, but I have not yet seen one from the lake with more than three; such, however, do not seem common. Cleopatra guillemei Bgt. 1885 Cleopatraguiliemei Esp. Nouv. Ouker. Tanganika, p. 6 . This species is included in Germain’s list of 1 9 2 0 , but I can find no authentic record of its collection in Lake Albert; possibly its occurrence there is based on water-worn examples of pirothi, which presents a very different appearance when it is in recent condition, covered with a blackish epidermis, to that of dead shells, which are smooth and glossy, with many gay patterns of vari-coloured spiral banding. Family U N IO N ID ^. Genus Parreysia Conrad. Parreysia acuminata (H. Ad.). 1 8 6 6 Unio acuminatus H. Ad., P.Z.S., p. 3 7 6 . Hab. Lake Albert (Baker); Kassenje (Stuhlmann; Schubotz); Ndandamira (Pitman); Butiaba (Mearns). An easily recognisable species, greatly resembling teretiuuula Phil.; it appears to be comparatively infrequent. Parreysia bakeri (H. Ad.). 1 8 6 6 Unio bakeri H. Ad., P.Z.S., p. 3 7 6 . Hab. Lake Albert (Baker; Emin); Kassenje (Stuhlmann ; Schu botz); Toro District (Fisher); Butiaba; Ndandamira (Pitman). Parreysia teretiuscula (Phil,). 1 83 8 Margarita ( Unio) cailliaudi F^r., Lea, Syn. Naiades, p, 24 (nomen nudum). 1847 Unto teretiusculus Phil, Abb. u. Beschr., iii, p. 4 5 , pi. iii, f. 3 , i856 do caillaudi Vir., Mts., Mai. filatt., p. 13. 1866 do do do H. Ad., P.Z.S., p. 3 7 6 . 18 8 8 do do do Smith, do p. 5 6 . 1S97 do teretimmlus Phil., Mts., D.O.A., iv, p. 2 2 9 . Lea’s reference being merely nomen nudum, the name awarded by Philippi is correct for this common Nilotic species, but I do not believe that the two bleached valves, on which the record is ba.sed, were collected in Lake Albert. They were originally labelled as from the Upper Nile, and arc of extremely low altitude, measuring 3634 X 15 and 35 X 14 mm. respectively, thus being exaggerated examples of the var. pnHaryi LongstafT, and as nothing approaching this form has since been collected in or near the lake, it is probable that they were actually picked up a considerable distance to the north of It. Genus Cffilatura Conrad. Caelatura egyptiaca (Caill.). 1S23 Unio egyptiacus Caill., Voy. i Meroe, Atlas, ii, pi. Ixi, f. 6 7. 1827 do agyptiacus do do do do iv, p. 2 6 3 . Hab. I,ake Albert (Baker); Kassenje (Schubotz); 'I’oro Dist. (Fisher); Ndandaniira (Pitman). Examples attributable to this species vary greatly, some appearing to grade into bakeri Ad., which can hardly belong to a diflerent genus ; egyptiacu$ and niloticus Caill., of which the former has priority, must be very near akin, and are inextricable from one another in most collections. mUTELID.®. Genus Aspatharia Bgt. Aspatharia stuhlmanni (Mts.). igoo Spatha stuhlmanni Mts., Simpson, Proc. U.S. Nat. Mus., xxii, p. 9 0 0 . 1927 Aspatharia do do P. & B., Bull. Amer. Mus. N.H., liii, p. 4 1 9 . Recorded by Simpson from Lake Albert, and subsequently by Germain, probably on the former’s authority; P. & B. point out that Simpson’s locality was erroneous, this mussel having been originally described from the Ituri District, west of the lake. Genus Mutela Scop. Mutela emini Mts. 1897 Mutela nilotica Caill, var. emini Mts., D.O.A., iv, p. 2 5 3 . 1927 do emini Mts., P. & B., Bull Amer. Mus. N.H., liii, p. 4 3 5 ; pi xlii, f. 2 . Hab. Lake Albert; Kassenje (Stuhlmann and probably Schubotz); Toro District (Fisher); Butiaba; Ndandamira (Pitman). 178 joohnaL of conchology, vol. i 8 , no. 6, bbceMbkr, 1927. From examination of specimens from the Fisher and Pitman collections, I certainly concur with P. & B. in awarding this race full specific rank; it is far more inequilateral than niloiica. Mutela alluaudi Germ. 190 9 Mutela alluaudi Germ., Bull. Mus. Paris, p. 5 4 4 ; pi. viii, f. 4 5 . Hal). Lake Albert (Alluaud); Toro District (Fisher). The solitary example collected by Mrs. Fislier agrees with tlie original description and figure in all respects except that while its altitude is the same as the type, its length is about 6 mm. less. Germain described this species from Lake Albert, but omitted it from his faunal list of 1920 ; it appears to be a valid species, and its re-discovery confirms the locality ; it is proportionately of greater alti tude than emini, and more regularly rhombic. Family CY REN ID ^. Genus Corbicula Muhlf. Corbicula pusilla ‘ Parr.’ (Phil.). 1846 Cyrma pusilla Parr., Phil., Abb. u. Beschr., ii, p. 7S ; pi. i, f. 7. 1865 Corbicula do Phil., H. Ad., P.Z.S., p. 3 7 6 . Corbicula radiata ‘Parr.’ (Phil.). 18 4 6 Cyrena radiata Parr., Phil., Abb. u. Beschr., ii, p. 7 8 ; pi. i, f. 8 . 18 6 6 Corbicula do Phil., H. Ad., P.Z.S., p. 3 7 6 . do do do P. & B., Bull. Amer. Mus. N.H., liii, p. 3 4 1 . Corbicula radiata edwardi P. & B. 1927 Corbicula radiata edwardi P. & B., Bull. Amer. Mus. N.H., liii, p. 3 4 3 ; text fig. 73 (described from L. Albert Edward). As almost every intermediate occurs, I do not attempt to discrim inate between the above forms ; the localities are Lake Albert (Baker; Emin; Schubotz); Kassenje (Stuhlmann); Kiboro (in British Museum); Toro Dist. (Fisher); Butiaba and Ndandamira (Pitman). The series from the last two stations embraces nearly every con ceivable admixture of sculpture and coloration, from almost smooth and glossy growth wrinkles to close, sharp, concentric striation, while the colour, quite independently of the sculpture, is dark green, shading to grey at the umbones or with a pale yellow marginal girdle; pale green, bluish grey, brown, bright yellow, flesh white, sometimes with a single lilac ray, when it is extremely delicate and beautiful, and finally combining with many of the foregoing the typical radiate um bones of radiata. The interior is impartially dark grey, pale yellow, or vari-coloured, occasionally corresponding exactly to the rayed exterior. As pointed out by the present writer in 1925 and liy P. &, H. (I.e.) tlie name radiata of Philippi is preoccupied and cannot lie retained, but it is difficult to determine without doubt by wliai name it should be replaced. PusiUa was bestowed on a race of very pale yellow shells from the Upper Nile, of which there is a set from As.souan in the Uritish Museum, received from Parreyss ; they are remarkable for their extremely weak sculpture, and accordingly glossy appearance, and I do not think it pos.sib)c that, as has been suggested by I’allary, they could ever develop into the large, coarsely sculptured a>nso/>n'iiii Caill. On the other hand, the sculpture of typical radiata, consisting of close, regular, clean cut concentric cosuite, resembles very nearly that of consobrina in its earlier stage of growth, and they may po.ssibly be conspecific, but if so, it is strange that nowhere else throughout Africa does radiata attain more than half the dimensions of the large Nilotic consobrina ; whether it would do so under Nilotic conditions can only be proved by experiment. Consobrina is, of course, the oldest name in this group; pusilla has page precedence over radiata, while if all the three are distinct, africana Krs., 184 8 , is available to replace radiata Phil.
Family SPH^CRIIU/E. Genus Sphaerium Scop. S phasrium nyanzx Smith.
1892 Spharium nyanzcc Smith, A.M.N.H., x, p. 3 8 3 . Hab. Lake Albert (Schubotz); Toro Dist. (Fisher); Butiaba; Ndandamira (Pitman). Genus Eupera Bgt. Eupera parasitica ‘ Parr.’ (Desh.). 1854 Pisum parasiticiim Parr., Uesh., Cat. Conchif., p. 2 8 0 . Hab. Lake Albert; Toro Dist. (Fisher); Butiaba; Ndandamira (Pitman). As P. & B. (I.e. p. 3 5 7 ) mention that the dimensions of the type of this species have never been published, I may state that its measurements are; long., 5,2 ; lat., 3 .6 ; diam. circa 2 .8 mni. The specimen most nearly approximating to it in siae from Lake Albert is 5.6 x 3 ,9 mm. in length and altitude. With a good representation of E. /crru"inea (Krs.) before me for comparison, I agree with Smith that the North African parasitica is quite distinct from the South African ferruginea, but it appears doubt ful whether the other Nilotic and Abyssinian forms, described by Bourguignat and his disciples, are separable from that of Deshayes. THE MOLLUSCA OF LAKE ALBERT NYANZA.
I)y M. CONNOLLY.
(Read before ihe Socicty, May 7th, tpa?}. \CoHcbidtd/roHi p. 179].
(b) FOSSIL SPECIES. The Kaiso fossils were obtained from a Ijed of ferruginous sand stone, whose age, based on the exatnination of vertebrate remains from the same locality, has been determined as late I’liocenc or Plio- Pleistocene, which is rather remarkable in view of the fact that none of the MoUusca represent species now living in Lake Albert, and that most of them are extinct, whereas other deposits, referred to as old, or an older age, by the authorities on vertebrates, contain extremely few Mollusca other than are still living in situ or in other parts of the Continent. As Cox aptly remarks, this extraordinary fossil fauna must show that the conditions of molluscan life in Lake Albert have changed very much for the worse, in comparison with some of the other lakes, when so many species have decreased in stature or died out, during the same period in which, in other localities, there has been little variation, or even an increase in size of their inhabitants. Family V IV IPA R ID ^. Genus Viviparus Montf. Viviparus alberti Cox. 1926 Viviparus alberti Cox, Geol. Palseont. Kaiso, p, 5 8 ; pi. viii, f. ’■3- Hab. Kaiso, East of Lake Albert (Wayland) : I will not repeat the locality, as all the fossils were collected there by him. Viviparus waylandi Cox. 1 9 2 6 Viviparus ivaylandi Cox, I.e., p. 5 9 ; pi. viii, f. 6 -7. Viviparus turris Cox. 19 2 6 Viviparus turris Cox, I.e., p. 5 9 ; pi. viii, (. 8 . Viviparus sp. n. 19 2 6 Viviparus sp. nov. “A,” Cox, I.e., p. 5 i ; pi. viii, f. 10. A remarkable form, which may belong to Pita rather than the present genus, but so far only fragments lacking the spire have come to hand. Viviparus dubius Cox.
1 9 2 6 Viviparus {Neothaum.i ?) dulnus Cox, I.e., p. 6 0 ; pi. viii, f, 4 , 9 . Apparently a A’eotkauma, and very interesting as pointing to former connection between Lakes Albert and Tanganyika. Family T H IA R in^., Genus Thiara Bolten. Thiara brevissima Cox. 1 9 2 6 Thiara brevissima Cox, I.e., p. 6 3 ; pi. ix, f. 1-2. Genus Cleopatra Tro.sch. Cleopatra cf ferruginea (Lea). 1926 Cleopatra cS. ferruginea Lea, Cox, I.e., p. 65 ; pi. viii, f. 5. Family UNIONII)i«i. Genus Cxiatura Conrad. Caslatura sp. 1926 Unio (^Nodularia) sp. indet., Cox, I.e., p. 6 7 . Genus Parreysia Conrad. Parreysia sp. 1926 Unio {Parreysia) sp. nov., Cox, I.e., p. 6 8 ; pi. ix, f. 4 . Family M U TELID ^. Genus Pleiodon Conrad. 1926 Pliodon sp. nov., Cox, I.e., p. 6 g ; pi. ix, f. 5 . Another noteworthy occurrence of a genus, chiefly confined to L. Tanganyika, in the earlier age of Lake Albert. Genus Mutela Scop. M utela sp. 1926 Mutela {Mutelhia) sp. indet., Cox, I.e., p. 6 9 ; pi. ix, f 3 . Closely related to .5/. alluaudi Germ., but of greater proportionate length ; although slightly deficient at each end, it measures 100 x 37 mm. in length and height, with a thickness of 21 mm., while alluaudi is stated to be 8 4 x 37 mm. and 31 mm. in diameter. Family ETHERIID.®. Genus E th eria Lam. Etheria elliptica Lam. 1807 Etheria elliptica Lam., Ann. Mus. H.N. Paris, x, p. 401 ; pi. 2 9 ; pi. 3 1 , f. 1. 1926 Aetherid elliptica Lam , Cox, I.e., p. 6 7 . It is remarkable that this widely diffused species, although abundant in live condition in L. Victoria Nyanza, appears to have become extinct in Lake Albert. It will be seen from the foregoing pages that if we eliminate Potadoma liricincta and tornata, Cleopatra guillemei, Parreysia teretius- cula and Aspatharia stuhlmanni, owing to their actual existence in the lake being unproven, there remains a total of twenty recent species 207 CONNOI.LV : THK MOIXUSCA 01' I.AKK AI.BKBT NYAN?.A. now known to inhabit it, while the fossils amount to twelve, none of which, with the possible exception of Mutela alluaudi, occur there in recent condition, and two of the genera, Pleiodon and Etheria, do not appear in its recent representation. Collections of fossils, containing a few freshwater shells, have been recorded from only five other districts in Central Africa, and it may be not without interest to summarise them here: (rt) The lake plain at the north-west corner of Lake Nyasa (vide liullen Newton' and Connolly®). This deposit, which Bullen Newton very reasonably considered, on conchological grounds, to be quaternary, has since been determined, owing to vertebrate remains, as of late Miocene age ; the mollusca are Lnnistes solidus Smith or ovum Ptrs. ; Cleopatra buHmoidts (Oliv.); Viviparus unkotor (Oliv.); Melanoidcs tuberculatus (Miill.); Cleopatra ftrruginea (Lea); Corbkuta africana (Krs.). {h) Gottorp, Tanganyika Territory (vide Dietrich’ ). Presumed to be of late tertiary age, the deposit only contained a single aquatic species, which Dietrich described as new under the name of Lanisies recki and compared with L. stuhlmanni Mts. (f) Miocene beds south of Kavirondo Gulf, Lake Victoria Nyanza (vide Bullen Newton*): Pila ovata (Oliv.); Lanistes cariuatus (Oliv.); Cleopatra bulimoides (Oliv.); Cleopatra exarata Mts. {d) Deposits of late Tertiary or post-Tertiary age near the south west corner of Lake Albert Edward (first mentioned by von Martens, and epitomised by Germain') : Planorbis sudanicus var. major Mts.; Planorbis choanomphalus Mts,, cum var. basisulcatus Mts. ; Viviparus (Oliv.) var. conoidea Mts.; Bulimus alberti {Sm\\h) ; Bulimus humerosus (Mts.); Melanoidcs tuberculatus (Miill.); Unio ngesianus Mts. ; Corbicula radiata (Phil.). (<) Beds near Kasinga, at tlie north-east corner of Lake Albert (vide Cox, 1. c. 1 9 2 6 ), which are supposed to be of the same age as the Kaiso deposits of Lake Albert Nyanza : Viviparus unicolor (Oliv.); Viviparus sp. n., but imperfect; Cleopatra bifidicincta Cox, sp. n .; Cleopatra sp. (?). I make no special mention of yet another deposit, which Smith” considered to be of late Post-Pliocene age, at Sumbu and the Rukwa Valley, near the East shore of Lake Tanganyika, as the material collected there was not sufficient for proper determination.
Q.J.G.S., Ixvi, 1910, p. *39. Do. Ixxxiii, 1937, p. 444. O nlralbl. Min., rgaj, p. 316. Q .J. G.S.. l*x. T914, p. 187. Bull. Mus. P a m , 1916, p. 193. P.Z.S., 1906, p. 15- Three points of interest will be noticed in tlie foregoing dis- trilmtion : Tlie first is that no really extinct species have occurred in deposits (