SUulii'S ou iiiai'inr t)>lracO(.ls 299 



Seventh 1 i in h: — This is furnished with a moderate niunber of cleaning bristles 

 a large ^jart of which are situated close together distally, the rest being scattered on the dorsal 

 and ventral edges somewhat proximally of these; with regard to the situation of the scattered 

 ])roximal bristles it is to be noted that we never find more than one bristle on the same side of the 

 same joint. The end comb consists of a moderate number of rather powerful teeth, among 

 which can be distinguished distally rounded or more or less j)ointed distal teeth, l)are or with 

 only a weak spine on each side at the middle, and also bare proximal teeth cut off transversalh- 

 distally. Dorsally, close to the end comb, the wall of the limb is very much thickened, 

 strongly chitinized and also deeply concave. The ventral portion of the wall in this concavity. 

 the part that is enclosed by the end comb, is continued proximally as a powerful chitinous 

 process, to which tlie chitinous part that forms the dorsal wall of the concavity is moveablv 

 joined. The dorsal and ventral walls of this concavity can be pressed together like a jaw; wlien 

 this occurs the distal tooth of the end comb is also brought against the dorsal wall of the concavitw 

 This compression takes place by means of a short, .powerful, paired muscle, issuing proximally 

 somewhat proximo-dorsally of the point of the limb and fixed distally to the proximal process 

 nl the chitinous plate that forms the ventral wall of the concavity. 



■ Furca: — The lamellae are moderately elongated. The number of claws is a])ouf 

 eight; the division into main and secondary claws is rather faint. 



The upper lip has three glandular fields, one dorsal, unpaired, directed forwards and 

 downwards and two ventral ones, paired; they are all separated from each other by deep furrows. 

 There is no large and conspicuous process. Dorsally of the lip there is an unpaired protuberance. 



The late r a 1 e y e s are well developed. 



Remarks: — Of this sub-genus only the species dealt with below — the type species — yuniOer of .■^pcvie^ 

 is known with any certainty. It seems, however, not impossible that at least one species that 

 lias been previously described is also to be included in this sub-genus, namely Ci/pridina nobilis 

 W T. Clbve (1905a, p. 134, pi. VII, figs. 3—5, 8; pi. VIII, figs. 10, 11; pi. IX, figs. 15—18, 22). 

 lor this species, as far as one can judge, has posteriorly on the shell a siphon similar to thai 

 which is characteristic for tlie form dealt with here. The incomplete description does not, 

 however, permit of any definite decision in this question. 



Whether Cypridina hirsuta G. W. MuLLKR (1906 a. p. 131. ])1. XXXIII, figs, l^l(i) 

 Ijelongs to this sub-genus is a still more difficult question to decide; it is, however, not impossible 

 that this is the case. 



In my opinion tlie most interesting point about the species described above is that, il /i' luuon lo t/iv gmtiis 

 I am not mistaken, it may perhaps make it possible for us to understand the systenmtic position 

 of the genus Heterodesmus. 



This genus was established by GI. S. BliADY, 18G5, p. 387, and was based on a single 

 species, H. Adamsi. The description of this species is exceedingly incomplete and also presumably 

 partly mcorrect; only some characters of the shell are mentioned, ,, animal unknown". In the 

 above-mentioned work the genus Heterodesmus was placed in the family Cypridinidae. In 

 a later work. 1868 b, ]). 358 the same author makes this genus, together with the geiuis 



Ifflciodcsinii:' 



