688 SIR c. ELIOT ON NUDiBRANCHS [June 1 9, 



much paler than Alder and Hancock's, but has a faint pmk tinge 

 in places, particularly on the rhinophores. 



In any case, Phyllohranchus orientalis A. & H. is the type of 

 the genus, and the points in doubt can probably be settled by an 

 examination of specimens from Ceylon. Phyl. viridis B., from, 

 the West Indies, and Phyl. horgninii Ti'inchese, from Naples, 

 seem to be distinct. 



E L y s 1 1 D ^. 



Though the genera Elysia and Placohranchus are clearly 

 distinguished, it does not seem to me that the differences between 

 the two groups called by Bergh Elysiidte and Placobranchidfe are 

 sufficient to constitute two families. 



The whole family (comprising Placobranchus, Elysia^ Tridachia, 

 Thuridilla, Elysiella, and Bosellia) is nearly related to the 

 Limapontiidse, which differ in the reduction of the tentacles, the 

 absence of lateral expansions of the body, and the slight rami- 

 fications of the liver. Elysiella and Bosellia seem to be connecting- 

 links, but neither genus is well known. The genus T]n(,ridilla is 

 well characterised : there is a buccal crop, and the anal papilla is 

 median and posterior as in Alderia. But the distinction between 

 Elysia and Tridachia is less satisfactorj^ In the latter genus the 

 wings are very ample with crinkled margins, and in the type 

 species {T. cris2xita) united behind the head. But this connection 

 between the two wings seems not to occur in the other species. 



Bergh (Journ. Mus. Godeffroy, i. 1873, pp. 79-80) gives a list 

 of twenty species of Elysia. Of these, the Elysia sp. Schramm 

 may be omitted. It is almost certainly identical with one of the 

 species created by Verrill, and, as it is nameless, has no claim to 

 be maintained. Elysia nigropunctata (Pease) 1871 appears to 

 be the same as the earlier E. punctata Kelaart 1859. I have not 

 been able to identify the animal cited as Elysia neap)olitana d'Ch. 

 without a reference. 



Since the publication of this list several species have been 

 described, of which E. lineolata Bergh seems to be clearly a 

 synonym of E. cceridea Kelaart. E. hendersoni Eliot is not 

 characterised in sufficient detail. Other species are : — 



19. E. dubia Eliot. East Africa. 



20. E. ornata Yerrill. Bermuda. 



(There is a Pterogastron ornatum Pease, which may 

 be an Elysia and have priority for the specific 

 name.) 



21. E. suhornaia Verr. Bermuda. 



22. E.flavaYevT. do. 



23. E. picta Verr. do. 



24. E. jxipillosa Yerr, do. 



25. E. thysanopoda Bergh. Malay Archipelago. 



26. E. haingsisiana Bergh. do. 



27. E. crispa Verr. Bermuda. 



