PLEUROBRANCHUS. 207 



passing the mantle behind, somewhat pointed. The mantle is a lit- 

 tle raised behind to form a gutter below. Entire body reddish, 

 covered with violaceous tubercles which are slightly yellowish ; a 

 brown band borders the upper surface of the foot. Labial tentacles 

 long. Length not over 10 lines. 



Amboyna. 



P. cornutus Q. & G., Zool. Astro!., ii, p. 298, pi. 22, f. 20-24. 



Quoy & Gaimard remark that the individual described seems to 

 be young. 



P. PERONII Cuvier. PI. 48, figs. 24, 25, 26, 27, 28 ; pi. 74. figs. 



88, 89, 90. 



Living animal oval, convex, the mantle notched in front, shorter 

 than the foot behind ; closely covered with round, low tubercles, 

 each on a red ground is bounded by a ring of deep crimson lake, 

 with a dot in the middle (see fig. 28, enlarged). The sides of the 

 foot are also dotted with this color. Veil slightly bilobed ; eyes 

 distinct. Shell very delicate and thin. Length 2 to 3 inches. 



In alcohol the red color changes to a yellowish tint, and the re- 

 lative proportions of foot and mantle are different, the foot becom- 

 ing smaller ; tuberculation of mantle obsolete. 



Port Louis, Mauritius. 



Pleurobranchus peronii CUVIER, Ann. du Mus. d'Hist. Nat., 

 v, pp. 275, 266, pi. 18, f. 1-6 (1804). QUOY & GAIMARD, Voy. de 

 1'Astrol. Zool., ii, p. 296, pi. 22, f. 7-10. DESK, in Cuvier's Kegne 

 Animal, Moll., p. 88, pi. 32, f. 1, a-i. MARTENS in Mobius' Meeres- 

 fauna Mauritius, p. 309. SOWERBY in Conch. Icon., xvii, f. 2. 



Quoy & Gaimard declare the species described from life by them 

 (see above) to be undoubtedly the same as that upon which Cuvier 

 established the genus. The latter was much contracted in alcohol 

 and had changed in color and form. An alcoholic specimen is 

 shown in figs. 88, 89, 90 of plate 74, the figures being copies of 

 Cuvier's original illustration of P. peronii. 



The figures of Deshayes, cited above, are perhaps not referable to 

 this species. 



Mobius thus describes the specimens found by him in Fouquets 

 Bay, Mauritius : Dark purple-red, the back lighter in the middle, 

 the mantle with low rounded warts throughout ; sole also dark pur- 

 ple-red, but somewhat bluish. Shell likewise of a beautiful purple- 



