REPOET ON THE NUDIBRANCHIATA. 
65 
and sufficient description of its characters. The genus Goniobranchus of Pease, 1 I am 
inclined, from an examination of his typical species, to consider identical with Chromo- 
doris. The genera Glossodoris, Actinodoris, and Pterodoris of Ehrenberg, established in 
1831, differ only in unessential and inconstant characters of the branchia, and hence 
must be incorporated with Chromodoris ? The genus Doriprismatica of d’Orbigny, 
established in 1834, must also be regarded as merely a variety of Cliromodoris. 
I have of late years examined a great number of species of this genus. 
Cliromodoris, in form and outward characters, resembles rather closely the very 
different Goniodoris, and on this account the two genera have been frequently confused ; 
but the colour, even, is quite different. 
The tentacles are small and conical ; the retractile rhinophoria have a perfoliated 
club. The edge of the mantle is prominent, and usually forms a frontal and caudal veil. 
The retractile branchia is formed of simply pinnate leaves. The armature of the labial 
disk is strong, and composed of a number of densely-set small hooks, bifid at the tip. 
The radula contains no rhachidian teeth, but there are frequently thickenings which take 
their place. The lateral teeth are numerous and hook-shaped ; the first lateral tooth is 
denticulate on both sides, the rest denticulate only upon the external margin ; the 
outward teeth are smaller, and denticulate at the extremity. The penis is unarmed. 
The genus Cliromodoris is readily distinguished by its external characters from 
Casella ; from Aphelodoris it differs by the armed condition of the labial disk, and by the 
characters of the branchia. As far as is known at present, the genus is confined to the 
tropics, or at least the warmer seas, and is the most abundant genus of the Family 
Dorididse. Practically nothing is known concerning its habits and development. 3 
The following is a list of the known species : — 
1. Cliromodoris zebrina, Alder and Hancock. 
Indian Ocean. 
2. Chromodoris elisabethinci, Bergh. 
1 Doris quadricolor, Lenckart. 
? Actinodoris sponsa, Ehrenberg. 
Philippine Sea. 
3. Chromodoris annce, Bergh. 
Philippine Sea. 
1 Amer. Journ. of Conch., vol. ii., 1866, p. 204. 
2 Bergh, Kritische Untersuch. d. Ehrenherg’schen Doriden, Jalirb. d. deutsch. malakoml. Gesellsch., Bd. iv., 1877, 
pp. 52-58. 
3 Pease, Amer. Journ. of Conch., vol. vii., 1871, pp. 15, 19. 
(ZOOL. CHALL. EXP. PART XXVI. 1884.) ' Cc 9 
