HuTTON. — On the Bitentaculate Slugs of New Zealand. 15^ 



The only specimen of J. papillata that I have had for dissection was in 

 such a bad state of preservation that I was unable to make out the details of 

 the alimentary and reproductive systems, but I saw enough to convince me 

 that they are constructed essentially on the same plan as those organs in the 

 other two species ; in fact I think that it may be only a variety of J. hiten- 

 taculata. I propose, therefore, to give a general account of the anatomy of 

 the genus, and also to point out the differences between J. hitentaculata and 

 J. marmorea. I have to thank E. W. Fereday, Esq., for living specimens 

 of J. hitentaculata vfh.ich. he found on flax {Phormiuni) at Fendal Town, near 

 Christchurch. 



External characters. The anus is situated on the right side, below and 

 a little in front of the pulmonary opening. The reproductive organs open 

 behind the right eye-peduncle, (fig. 1). There is a mucous pore situated 

 on the dorsal groove, just in front of the pulmonary opening. The foot is 

 scarcely distinct from the body, and shows no locomotive disc, but after the 

 animal has been placed in strong spirit a lateral groove appears on each side, 

 and the foot shows three longitudinal grooves, a broad central one, and a 

 narrow one on each side, (fig. 2). Twelve to sixteen minute calcareous 

 plates form a rudimentary shell. They are situated inside the pulmonary 

 cavity ; the largest in front of the opening, and the others forming a row on 

 the inner or left side of the opening, (fig. 16). These particles have been 

 figured by Dr. Knight, (" Trans. Lin. Soc." xxii., p. 881.) 



Alimentary system (figs. 4 and 5). The buccal mass is large, and of 

 the ordinary shape, but the retractor muscles arise from the musculature of 

 the foot, immediately under the nerve collar. The length of the radula is 

 not quite twice its breadth, and each half is rolled up into a separate spiral 

 (fig. 4 c), as figured by Dr. Knight in his paper already quoted. The 

 teeth are about 255-1-255, varying slightly in number, and there are about 

 130 transverse rows. The central tooth is about ^-^^^ of an inch in length, 

 and varies considerably. In J. marmorea the anterior end is emarginate, 

 and there is no central cusp (fig. 9). In J. hitentaculata there is a 

 central cusp, and the anterior end is either simple or has a central swelling, 

 which is either single or divided into two (figs. 10, 11, and 12). In the 

 single specimen I had of J. papillata the central teeth were hke figs. 10 and 

 11, but none like fig. 12. There is no distinction between lateral and mar- 

 ginal teeth (figs. 13 and 14) ; all are alike, and similar in all the species. 

 They have been very accurately figured by Dr. Knight. The inner laterals 

 are rather more than x^^ott °^ ^^ ^^°^^ ^^^ length, and they gradually 

 diminish to about half that size at the margin. They are arranged on 

 the radula in transverse lines that form an obtuse angle, pointing anteriorly, 

 (fig. 8). 



