and Speri«\f of Siulihrtinrhiatf MoUusra. 135 



gcnprally with corneous j;iws ; odoiitopliore broiulj with iiuiik^- 

 rous lateral .sj)iiifs in (>aoh tninsverse row. 



The ;:rtMiiis was constituted by Ehrenbcrg in 1831*, to 

 inohulo II. pratf.rtus described by him, and Doris lacera of 

 Cuvier t- The following may also be referred to tlio genus : — 

 Dvris marijiutita antl D. ffanunuhita (?), descri]:)ed and figured 

 by Quoy and (.rainiard J; />. sawjuiuca^ Riippell §; D. sand- 

 ictc/iensi's, Souleyet ||; JI. Adamsi^ Gray ^ ; and D. superba, 

 D. cardinalisj and D. sumpttiosa of Gould **. It is more 

 doubtful whether Ileptohranchns Burnct(n\ Adams, and Doris 

 (R/mrodon'ii) I\rcf>sii\ Milrchft, should also be included in the 

 ffenus. According to Adams's description and figure \\, the 

 former would seem to have all the more important characters 

 of the Ilexabranchs, with the exception of having the bran- 

 chial bundles arranged round the anus " in a broad lunate 

 series," instead of in a circle — an appearance which may have 

 been due to the state of contraction of the specimen, and 

 wiiich, at any rate, is not, of itself, of sufficient importance to 

 constitute a genus. lS\. ^liirch has proposed '■'' lihacodoris^' as a 

 subgenus of Don's, to include the Mollusca of the type D. 

 lacera, Cuvier, which he considers to have been wrongly 

 referred to Hexahranchus, Ehx*. He states that in the latter 

 the branchial plumes are separately retractile in cavities as 

 well as collectively into a common brancliial cavity — an idea 

 which also obtains in Adams's ' Genera t!i:c.' In most of the 

 descriptions, including those by Cuvier, ?Lhrenberg, and liiip- 

 pell, the non-retractibility of the branchia? is given as a cha- 

 racter. Of the twenty-nine s])ccimens (representing five or 

 six species) in the British-Museum collection, none shows any 

 trace of retractile branchiae. Judging from the imperfect 

 description, lihacodoris Krebsii will probably prove to be a 

 species of Doridopsis §§, 



* ' Syrabola? Plivsicse ' — Animalia evertebrata exclusis insectis. 



t Annales du Museum, vol. iv. p. 453, pi. Ixxiii. f. 1-3. 



\ Voyapre de I'Astrolabe, vol. ii. pp. 255 & 257, pi. xvii. f. 1-5, G-10. 



§ Atla.*! vou E. Riippell, ' Xeue wirhellose Thiere de.s rothen Meers,' 

 p. 28, T. viii. f. 1, 



II ' Vovage autour du Monde sur la Bonite,' Zoologie, torn. ii. p. 451, 

 pi. XXV. i. i-4. 



U ' Figures of Molluscous Animals,' vol. iv. p. 104, tab. 219. f. 1. 



•• ' Otia Concholojrica,' po. 228, 22!». 



tt In ' Journal de Conchyliologie,' vol. xi. p. 34. 



XX 'Genera of Recent Mollusca,' vol. ii. p. 50, pi. Ixiii. f 10. 



§§ Since the above was in type, the a\ithor has found that D. Krehni 

 has recently been dissected and aescribed by Berffh (in 'Journal des Mu- 

 seum Godeffrov,' Heft viii. p. B7), and shown to oe a Doridopsit. 



\0* 



