572 GASTROPODA. [Opisthobranchia. 



It occurs in the Mediterranean and Cape Verde Islands. In the 

 Pacific it is recorded from as far north as Japan, and on the American 

 coast from Puget Sound and Monterey ; in the south from New Zealand, 

 Tasmania, and Juan Fernandez, also from South Africa. 



Over a hundred species have been described. They are common 

 on coral reefs and in pools filled with seaweed. Their brilliant colora- 

 tion, which is often dazzingly gorgeous in the living animal, does not 

 appear to in any way harmonize with their environment. On the 

 other hand, some of the most striking species are commonly found 

 under stones, where their hues can be neither "protective'' nor 



" warning." (Eliot.) 



KEY TO SPECIES. 



A. Colour of clorsuin pink or purple, with a central row of 



oblong orange spots, occasionally a few lateral ones . . amcena. 



B. Colour of dorsum white, with an orange line within the 



mantle-margin, which, however, is soon lost in spirit 



specimens . . . . . . . . . . aureo-marginata. 



C. Colour of dorsum white, with 3 rows of roundish orange 



specks, which become milk-white in alcohol . . . . atopa. 



1. Chromodoris amoena, Cheeseman. 1886. Plate 37, fig. 5. 



Chromodoris amcena, Chsm., T.N.Z.I., xviii, 1885 (1886), 137 ; Eliot, P. ilal. S., 

 vii, 1907, 329, 345. C. figurata, Bergh, Sernper's Reise Philipp., Malac. 

 Unters., vi, pt. 2, 1905, 71. 



Body linear-oblong, rounded in front, pointed behind, back slightly 

 convex. Mantle smaller than the foot, quite smooth and even. Colour 

 of dorsal surface pale-pinkish or purplish-lilac, with a central row of 

 large bright-orange oblong spots, and occasionally a few lateral ones, 

 margin pale-creamy or yellowish-white. Rkinophores clavate, com- 

 pletely retractile within slightly raised sheaths ; upper part arched 

 backwards, with 20 to 25 lamina?. Branchice completely retractile, 

 varying from 8 to 10 in number, connected at the base, small, erect, 

 linear, simply pinnate, but sometimes bipinnate, being divided into 

 2-4 plumes at the tip. Rhinophores and branchiae are a bright- 

 magenta colour. Oral tentacles free, small, conical. Foot paler than 

 the mantle, the sides and extremity with an irregular double row of 

 roundish bright-orange spots, considerably longer than the mantle ; 

 sole pale flesh-colour. Ova deposited in a spiral coil of -i turns. 



Length 40-50 mm. Length, 23 mm. ; breadth, 10-5 mm. ; height, 

 10 mm. (spirit specimen). 



Buccal mass very large. Labial armature yellowish-green, and con- 

 sisting of rods somewhat bent or curved at the tip, which in some 

 parts of the armature is bifid, in others entire. 



Radula consisting of 65 to 90 rows, with 10 to 120 teeth on either 

 side of the rhachis. The latter bears a median tooth with a long base 

 and a low cusp, which is not denticulate, though of somewhat irregular 

 outline. The first lateral is of the shape usual in the genus, and is 

 denticulate on both sides, bearing on the inner side about 4 denticles. 



