1895.] NATURAL, SCIENCES OF PHILADELPHIA. 349 



It would therefore seem that Linne originally intended Tethys for 

 the Aplysia species, his generic diagnosis and references unmistaka- 

 bly indicating the " Lepus inarinus " of the early zoological re- 

 naissance authors. 



In the Twelfth Edition of the Systema, p. 1089, Linne wholly 

 alters the diagnosis of Tetliys as follows: 



"289. Tethys. Corpus liberum, oblongiusculum, carnosum, 

 apodum. Os proboseide terminal e, cylindrica, sub labis explicate. 

 Foramina 2 ad latis colli sinistrum. 

 " leporin. 1. T. labro ciliato. f 



Column, aquat. 27. t. 26. Lepus inarinus major. 



Rondel, pise. 526. Leporis marini tertia species. 



Habitat in Mari Mediterraneo. 

 "fimbria. 2. T. labro crenulato. 



Bohads. mar. 54 t. 5. /. 1, 2. Fimbria. 



Habitat in mari adritico. 



Videtur « prazcedenti distincti species.'" 



All of these references belong to the one Mediterranean species 

 (see Bergh in Semper's Reisen, 2ter Theil, ii, p. 348), known as 

 Tethys fimbria or leporina. 1 



On page 1,082 of the Twelfth Edition, the new genus Aplysia or 

 Laph/sia 2 is proposed, thus: 



" 283. Laplyssia. Corpus repens, obvelatum membranis reflexis. 



( 'lypeo dorsali, membranaceo, pulmones obtegente. 



Foramen laterale, dextrum, pro genitalibus. 



Amis supra extremitatem dorsi. 



1 The specific name of this Nudibranch must stand fimbria Linn.; the 

 binomial combination Tethys leporina being preoccupied by Linnseus 1758. 

 The synonymy of the genus is as follows: 



1761. Fimbria Bohadsch, 1761. (a mononym). 



1767. Tethvs L. 1767, not Tethys L. 1758. 



1801. Tethis Lam., 8vst. An. s. Vert. p. 63. 



1808. Thethys Cuvier, Ann. du Mus. d'Hist, Nat. XII, p. 257. 



1808. Thetis Meckel. Beytr. zu vergleicb. Anat. I. i, p. 9, not Thetis J. Sowb. 



Min. Conch. 1826. 

 1817'?. Thetrs Fir., Tabl. Syst. p. 28. 



1819. Phoenicjtnis Rudolphi, Entozoorum Synopsis, p. 573. 

 1823. Vertumnus Otto. Nov. A. Ac. C. Leop". Nat. Cur. XI, pp. 294-300. 



Of these names the first was not distinctly proposed as a genus, Bohadsch's 

 nomenclature being strictly mononymic. The seventh and eighth were founded 

 on minute appendages of the animal, supposed to be parasitic worms, and 

 certainly the genus could not be identified by these descriptions. The other 

 names are variants on Linnaeus' original Tethys. 



2 The spelling " Laplysia" is evidently a typographical error or oversight, 

 for the first use of the word, on page 1,072 of the Syst. Nat. 12, is in the correct 

 form " Aplysia." The generic diagnosis given on this page is brief, but sufficient: 

 " 283. Aplysia Tentacula 4. Anus supra postica." 



