202 PROCEEDINGS OF THE 1IALACOLOGICAL SOCIETY. 



ON THE 

 REDISCOVERY OF EUSELENOPS [=NEDA~\ LUNICEPS (Cuv.). 



By S. Pace, F.Z.S., etc. 



Read \\th January, 1901. 



The genus Neda was founded (October, 1854) by the brothers Adams, 1 

 for the reception of a remarkable pelagic Tectibranch which Cuvier 2 

 had previously (1817) named Pleurobranehis luniceps. Although 

 Cuvier published a figure of the species, he gave no diagnosis of its 

 characters, neither did he mention whence his specimen (evidently 

 a spirit one) had been derived. 3 In all probability, however, it had 

 been collected by Peron and Lesueur ; and it was probably the same 

 specimen which was afterwards (1826) described by De Blainville. 4 

 The species was evidently rediscovered by the " Samarang," since 

 coloured figures 5 by A. Adams of the living animal were included in 

 the account 6 of the Zoology of the voyage ; but, again, nothing was 

 said as to the occurrence of the form, and the specimen, if it were 

 preserved, cannot now be traced. 



Pilsbry 7 in 1896 pointed out that the name Neda was preoccupied, 

 it having been employed by Mulsant for a genus of Coleoptera, and he 

 therefore proposed to rename the Molluscan group Euselenops. Pilsbry 

 regarded Euselenops as a subgenus of Pleurobranchcea, but I think that 

 it will prove entitled to at least generic rank. 



Among the Opisthobranchs collected by Semper in the Philippines 

 was a single example of one which Bergh 8 regarded as being identical 

 with the type of Adams' genus Neda, and as probably the same as 

 Cuvier's Pleurobranehus luniceps. Bergh made no reference to 

 Pilsbry's work; and he established (December, 1897) the new genus 

 Oscaniopsis for Semper's specimen, renaming the species 0. Semperi. 

 Whether Oscaniopsis Semperi really is the same as the species figured 



1 Genera, vol. ii, p. 40. Neda was described as a genus of Pleurobrancbinse. 



2 Regne Animal, vol. ii, p. 396, footnote ; vol. iv, pi. xi, fig. 2. As first pointed 



out by De Blainville, Cuvier's figure has obviously been reversed by the engraver, 

 the gill appearing on the left side of the animal. 



3 Bergh in the course of his description of Semper's Pleurobranchidse states (footnote 



to p. 7) that Vayssiere has examined Cuvier's specimen, and that it is said to 

 come from Mauritius. 



4 Diet. Sci. Nat., vol. xli, p. 371. 



5 The " Samarang " figure was incorrectly copied on pi. Ixi of Adams' " Genera " ; 



an anal siphon, distinct from the tubular fold of the mantle, having been 

 inserted by the engraver. 



6 Adams & Reeve : Zool. Voy. Samarang (Mollusca), p. 66, pi. xviii, fig. 6. 

 " Tryon's Man. Conch., ser. i, vol. xvi, p. 228. 



8 In Semper: Reisen im Archipel. Philipp., pp. 54-57, pi. vi, figs. 11-31. 



