402 SIR C. ELIOT ON NUDIBRAXCHS [Mar, 1, 



variable, and does not lend itself to expression in a formula. 

 In most of the larger specimens it is somewhat as follows ; — • 

 All the branchiae rise from a ring which forms the common 

 support ; in front and behind (where it is united with the anal 

 papilla) it is about 4 mm. high. From it rise in front three 

 longish separate plumes, bifid or trifid a,t the ti]?. On each side 

 is a group of about five plumes, united together by a common 

 portion some 6 mm. high; each plume is divided into three or 

 four subdivisions, and each of these subdivisions is branched 

 again. 



The anterior margin of the foot is deeply grooved, but so 

 retracted in most specimens that it is hard to see. The tentacles 

 are also generally retracted. The buccal mass is a large elongated 

 yellow cone, and the retractor muscles are very conspicuoi;s. 

 The labial armature is composed of small slender hooks, rather 

 irregular in sha,pe but not bifid. The large radula is supported 

 by a stifl!" strong membrane, from which the teeth are not 

 easily detached. In the larger specimens the formula is about 

 150.0.150 X 70. There is a slight rhachidian fold. The inner- 

 most teeth have one denticle on the inner side and 3 to 4 on 

 the outer. The rest bear 1-3 inconspicuous denticles on the 

 outer side only, of which the highest is the largest. The outer- 

 most teeth are degraded, but not much seri'ulated. In one 

 specimen a number of ii-regular teeth, bifid and variously jagged, 

 occurred in the middle of several rows. The rest of the intei-nal 

 organs appeared to be as described by Bergh. There is haitlly 

 a.ny dilatation which can be called a stomach before the digestive 

 tract enters the liver. 



Genus SPHyERODORIS. 



This genus is characterised by its peculiar dentition, simply 

 pinnate bra,nchi?e, and the external conformation of the mouth- 

 parts. In outward appearance the species differ greatly, for 

 whereas punctata^ |j)a^9?7fo.^a, and verrucosa bear ridges and warts, 

 Imvis is smooth. Bergh classes the genus with Orodoris and 

 Miamira, apparently on account of these warts and ridges ; but 

 it appears to me to be more nearly allied to Chromodoris in 

 Adrtue of its simple bi^xnchise and its dentition, which is sub- 

 stantially similar, although it has peculiarities of its own. The 

 teeth are straight, long, and thin, with a comb-like denticulation. 

 The innermost are broader than the others and divided into two 

 parts, one of which is smooth and the other denticulate— an 

 arrangement which is perhaps analogous to that of Chr. mdrchii 

 and Chr. gonatophora^ where the innermost teeth have one large 

 smooth denticle on the inside and several small ones on the 

 outside, although in Sphcerodoris it would appear that the smooth 

 part of the tooth corresponds to the outside. 



Four species are known, all from the Indo-Pacific. 



