380 SIR C. ELIOT ON NUDIBRANCHS [Mar. 1, 



1. On some Nudibranchs from East Africa and Zanzibar. 

 Part IV.* By Sir C. Eliot, K.C.M.G., late H.M. Com- 

 missioner for the East African Protectorate, F.Z.S. — 

 Dorididoe Cryptobranchiatee, II. 



[Received January 23, 1904.J 

 (Plates XXIII. & XXIY.t) 



[The complete account of the new species described in this communication 

 appears here ; but as the names and preliminary diagnoses wei-e published in the 

 ' Abstract,' such species are distinguished hei'e by being underlined. — Editok.] 



In my last paper t I discussed the Cryptobranchiate Dorids 

 represented by such genera as Archidoris, Discodoris, Flatydoris, 

 (fcc. These are oval flattish forms, mostly of sombre coloration, 

 with a dorsal surface rarely smooth but generally granulated, or 

 bearing papillae, warts, or tubercles. The branchiae are usually 

 tripinnate. A labial armature is more often absent than present, 

 there is no central tooth, and the radula consists of uniform, 

 simply hamate teeth, rarely ditferentiated or denticulate. In the 

 present paper I propose to consider some forms belonging to 

 another group typified by Chromodoris and its allies. These 

 Dorids are often (but not always) elongated and limaciform in 

 shape, brightly coloured, and smooth. The branchise are usually 

 simply pinnate. A labial armature is nearly always present 

 (absent only in Thorunna and Aphelodoris). In the radula a 

 central tooth is rare, but sometimes occurs (in Gadlina, Tyrinna, 

 and Chr. scahriuscula), and rhachidian thickenings are frequent. 

 The teeth are generally denticidate, and the tooth next to the 

 rhachis is nearly always difierent in shape from the others. The 

 stomach is usually enclosed in the liver, and there is rarely any 

 armature in the reproductive organs. All these characters are 

 well seen in Chromodoris ; and I am inclined to think that the 

 following genera are more or less closely allied to it : — Casella, 

 Ceratosoma, Thorunna, Aphelodoris, Orodoris, Sphcerodoris^ 

 Cadlina, Tyrinna, Halla §, Rostanga, and Attdura. The common 

 character possessed by all these forms is in the mouth-parts : 



* For Part III. see P. Z. S. 1903, vol. ii. p. 354. 



t For explanation of the Plates see p. 406. 



X Since writing the third part of this paper {cf. P. Z. S. 1903, vol. ii. p. 354) I have 

 read the last fasciculus by Prof. Bergh which has appeared in Semper's ' Reisen ' 

 (Bd. ix. Th. vi. Lief. i. Nudibranchiata, January 1904), and it appears to me that 

 the genus Feronodoris is practically equivalent to that which I proposed to call 

 Sclerodoris, and as it has priority should take the place of the latter name. The 

 only difference in the generic characters is that for Feronodoris is given " penis stylo 

 amiatus." I did not see this style in anj^ of the forms which I have described, but 

 even if it is present in some species and absent in others, this variation would not in 

 my opinion necessitate the creation of separate genera. 



Archidoris violacea Bergh seems nearly allied to my A. africana, and A, nanula 

 Bergh to mj' A. minor ; but the identity of the forms, though not impossible, cannot 

 be demonstrated from the descriptions. 



§ [This name is preoccupied bj' a Polj'chsete \iOTia,Salla parihenopeia A. Costa, 

 Ann. Accad. d. Aspiranti Naturalisti Napoli, ii. p. 63 (1844).— C. Ceossland.] 



