1916.] Fauna of the Chilka Lake : Mollusca Nudibranchiata. 379 



The preserved specimen is 17 mm. long and of a uniform brown colour. The 

 shape is as described in the above notes. The rhinophores are very distinct. They 

 would be about 7 mm. long if straightened out, but are curved backwards into a 

 crescent shape and still remain remarkably tapering and pointed. Their surface is 

 smooth and under a lens presents no sign of a fold, but a section seen under the 

 microscope shows a shallow groove. But in life the organs can hardly have been 

 auriform as in most Elysiae. The wings are narrow and erect and the veins or 

 ridges on their inner sides are prominent and conspicuous. The pericardial promin- 

 ence is large and distinct. It it somewhat distorted as preserved, but its natural 

 shape was probably oval. The external orifices appear to be placed as in E. viridis, 

 but are not easily seen. The foot is long, distinct and bipartite, the anterior portion 

 being marked off distinctly from the rest. 



The radula is of the type usual in the genus and contains 8 teeth in the ascend- 

 ing part, 16 in the descending part and 5 in the heap. The teeth resemble those of 

 Elysia faustula as described and figured by Bergh in his Malacogische Untersuch- 

 ungen (in Semper' s Reisen, Heft IV, pi. xxii, figs. 15-17. Cf. Eliot in Proc. Zool 

 Soc. London, 1904, p. 295). They are dagger-shaped, rather elongate and there are 

 no signs of denticulation on the lower edge. 



This animal is in most respects a typical Elysia, but it has long, tapering ten- 

 tacles which appear to be only slightly grooved, whereas in most species the tentacles 

 are rather short and distinctly folded or auriculate. E. lobata, Gould, from Honolulu, 

 E. (Actaeon) australis, Q. and G. and E. coodgeensis , Angas, both from Port Jackson, 

 Australia, and E. viridissima, Trinchese, from the Mediterranean are all said to have 

 long tentacles and the present specimen is very likely identical with one of them. But 

 in colour it does not agree with any of them. This is not an important discrepancy 

 for colouration is extremely variable in this genus, coloured borders and spots being 

 present or absent in otherwise similar specimens. Still in the absence of any agree- 

 ment as to colour it is impossible to identify our specimen with any of those known by 

 the somewhat meagre descriptions of the authors mentioned above and it must be 

 regarded provisionally as a new species, Elysia chilkensis. 



