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PAPERS AND PROCEJilDINGS OF 'rHE RoYAl. &>erFlTY OP TASMANIA, VOLUME 97 THE OCCURRENCE IN TASMANIA OF THE LAND NEMERTINE, GEONEMERTES AUST:~ALIENSIS DENDY, WITH SOME ACCOUNT OF ITS DISTRIBUTION, HABITS, VARIATIONS AND DEVELOP~ MENT. By V. V. HICKMAN (\ViLlI tvm Dlates and 20 figures in the t.ext) ABSTRACT INTRODUCTION The terrestrial nemertine, Geonemertes austral­ The terrestrial nemertine, Geonemertes austral­ iensis Dendy, is widely distributed in Tasmania, but iensis Dendy, was first recorded from Gippsland, is never found in large numbers. It occurs in Victoria, by Dendy in 1889 and described by him cool and moist situations from near sea-level to in 1892. Fletcher mentioned the occurrence of land the summit of mountains 4000 ft. in height. The nemertines in Tasmania and New South Wales in sexes are separate. Males reach <a maximum length 1891. He sent two specimens from these localities orfabout 60 mm. and females about 84 rum. The to Dendy, who remarlted (1892) in reference to coLour varies from pale cream to reddish brown. them: "it is somewhat doubtful whether they Some specimens are blotched with brown, others belong to the same species as the Victorian speci­ a.re marked with longitudinal dark brownish stripes. mens, <though from the examination of the external The nemertine feeds on young myriapods and small oharaders, which I have been permHted to make, insects, particularly Collembola, which it captures r am inclined to believe that they do ". with its pmboscis and kills with its stylet. The eyes Spencer (1892) stated that he found four speci­ vary in number from four in recently hatched speci­ mens in Tasmania, which he regarded as identical mens to over 170 in some adults. The number of with the Victorian species. Three years later in proboscidial nerves is es<tablished bef'Ore hatching. recording the occurrence of Peripatus insignis in An examination 'Of 187 adults and 374 young shows Tasmania he als'O remarked that 'at St. Clair. Dee the number ,to vary from 11 to 21, the most fre­ Bridge and Parattah he found "oonsiderable quent number being 14. Two reserve stylet pouches numbers of the land nemertine, Geonemertes are present in young specimens that have just australiensis ". emerged from the egg-capsule but as many as 11 may be present in adults. Haswell (1914) and Steele (926) have also men­ tioned the occurrence of the nemertine in this The gelatinous egg-capsules are deposited under State but have given no further details. logs, s.tones, moss, fallen leaves, &c. They vary in size from 8.0 mm. x 4.0 mm. to 48.0 mm.' x Flynn (928) remarked that a terrestrial nemer­ 10.0 mm. Small capsules may contain only four tine, probably of another species, was by no means eggs, whereas large ones may contain several rare in gulleys 'Of the lower slopes of Mount Wel­ hundred. One female may deposit as many as lington. seven capsules in· a period O'f two months. Egg In view of the zoological interest in terrestrial laying occurs throughout the year but appears to nemertinesand the li:ttle that has been recorded be most active in kpril and May. At a temperature concerning their occurrence in Tasmania, it seems 'Of 13 0 C. the eggs hSJtch in the gelatinous matrix in desirable to place on rec'Ord some observations about 15 days, but the newly hatched young are in which I have made during the past 30 years as a very immature condition and remain in the opportunity occurred. capsule for another 24 days. In spite of its marked variations there appears In the early stages of development cleavage is to be only one species in Tasmania and there is holoblastic, equal and of the spiral type. A typical no doubt that it is identical with Geonemertes hollow blastula is formed. Gastrulation is brought australiensis Dendy. I have been able to compare about by the ingression of blastomeres into the Victorian and Tasmanian specimens and can find blastocoel at the vegetative pole. At the same time no justificatton for rega,rding them as different cells separate off from the inner ends of the blasto­ species. In the course of the present study over meres forming the wall of the blastula and fall 200 speci:mens of the nemertine and many egg­ into the blastocoel. These cells constitute mesecto­ capsuIes hav.e been collected from different parts derm. The blastocoel becomes filled with a mass of of the State. cells and its lumen obliterated., The outer ends of the blastomeres remain as large yolky cells sur­ On acc'Ount of the work, carried out by Dendy rounding the embryo and supply nourishment to (1892) a detailed anatomioal study is not required. the proliferating mesectoderm. However, special attention is given to variations 63 64 OCCURRENCE IN TASMANIA OF THE LAND NEMER TINE in colOur, number Of eyes, and prO'boscidial nerves, deeply embedded stones. Large cream coloured &c. The main features of the embryonic develop­ specimens are generally found only in rain forest ment are also described. areas, whilst the darker reddish brown forms may be found in both rain forest areas and more open METHODS AND MATERIALS regions, such as the Trevallyn hills. Adult speci­ Observations O'n colour and lengtlh were usually mens may bo collected throughout the year. made on the living animal. For anatomical study As may be seen from Table 1 the nemertine is the nemertine was narcotised in the vapour of widely distributed in ,the State. In addi:tion to the chloroform and immedialtely placed in a fixative localities mentioned in the Table, it also occurs (Gilson's mixture, sublimate ac,etic or Bouin's picro­ near the Great Lake and Lake st. Clair on the forma}). Sections were cut at lOlL and stained Central Plateau, a;t Anson's Bay on the East Coast with Ehrlich's haematoxyHn, eosin being some­ and at Ca:tama,ran in the South. At Anson's, Bay times used as a oounter sbain. and Eaglehawk Neck it may be found almost at In order to obtain the eggs live specimens of the sea-lev,el and sometimes within a short distance nemertine were kept in the laboratory. No difficulty of the shore, However, it never occurs, in the was experienced in keeping them for six months splash zone. If placed in sea water it reacts or longer provided the temperature of the vivarium violently, ev.erting its broboscis and failing to sur­ did not rise above 23° C. A temperature of 27° C. vive longer than about 30 minutes. usually proved fatal. Hence during the summer, On some of the mountains it is found at oonsider­ when there was any danger of high temperatures able altitudes. Thus on Quamby Bluff, which has being reached, the specimens were transfel'red to a height of 4200 ft., it occurs at the summit. a cool chamber. Each female was ~ept in a At no locality have I seen the nemertine in large separate tin measuring about 10.0 cm. in diameter numbers and it is H common experience to search and 6.0 cm. in height. The tins contained moss, aI'eas, where it is known to occur, and yet not decaying leaves and rotten wood. The ma,terial find a Single specimen. was kept slightly moist and the tin closed with a lid. Collembolids were sometimes provided as food but usually sufficient small organisms were present HABITS amongst the moss and decaying leaves. In captivfty Geonemertes australiensis does not Gravid females collected in the field sometimes move about very much. Specimens will remain deposited their egg-capsules in two to four weeks in the one pOSition for three or four days in after being placed in the tins. To ensure fertility succession apparently waiting for their prey. When male specimens were usually placed with the at rest the nemertine is usually encased in a tough females. During summer many of the egg-c,apsules covering of mucus with only the fl'Ont of its head were destroyed by moulds. A similar destruction exposed. The mucus coalt extends forward for a wa,s also observed sometimes to occur in the field. short distance below ,and in front of the head form­ However, in autumn and winter the eggs developed ing 'a small area, which is covel'ed with viscid slime satisfactorily. The capsules were examined under secreted by the cephalic gland. If a small insect the dissecting microscope each day during the comes into contact with this area of sticky slime or course of incubation, habching in the gelatinous if it merely touches agains<t ,the body of the nemer­ matrix, and the emergence of the young from the tine, the resting animal suddenly everts its pro­ capsules. boscis in an attempt to capture the insect. Some­ From time to time portions of the matrix con­ times the prey is merely held by <the adhesive pap­ taining eggs at different stages of development were illae of the proboscis, but at other times the organ taken, fixed in Bouin's fiuid and sectioned. On is coiled partly round the v~ctim. The proboscis other occasi:ons the eggs were removed from the is extremely mobile and fiexible. A small speci­ fixed material and sectioned separately. To avoid men of the nemertine was observed to evecrt its rendering the yolk of the eggs brittle the time in proboscis and bend it round in order to capture the embedding oven was made as short as possible, a collembolid, Which was walking across the about 20 minutes. mtddle of its body.

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