SUiilii's uM inaiiiii- 0.slra<-otls 2i)9 



y e V e 11 t li 1 i HI h: — This is furnished with a moderate number of cleaning bristles 

 a large part 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 

 proximal 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 pointed distal teeth, bare or with 

 only a weak spine on each side at the middle, and also bare proximal teeth cut oil transversally 

 distally. Dorsally, close to the end comb, the w^all of the limb is very much thickened. 

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

 the part that is enclosed by the end comb, is continued proximally as a powerful chitinou.s 

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

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

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

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

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

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



F u r c a: — The lamellae are moderately elongated. Tlie number of claws is aljout 

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



The upper lip lias 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 lateral eyes are well developed. 



Remarks: — Of this sub-genus only the species dealt with below — the type species — .yumber oj si,ecU: 

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

 has been previously described is also to be included in this sub-genus, namely Cypridina nobilu 

 P. T. Cleve (1905a, p. 134, pi. VII, figs. 3-5, 8; pi. VIII, figs. 10, 11; pi. IX, figs. 15-18, 22). 

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

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

 however, permit of any definite decision in this question. 



Whether Cypridina Jiirsuta G. W. MOLLER (1906 a, p. 131, pi. XXXIII, tigs. 1—10) 

 belongs 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 the most interesting point about the species described above is that, if /trhuwuiu i/u- svii- 

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

 of the genus Helerodesmus. 



This genus was established by G. S. Bhady, 1865, p. 387, and was btised on a single 

 species, H. Adanm. Tlic description of this species is exceedingly incomplete and also presumably 

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

 above-mentioned work tlie genus Hetewdesmus was ]ilaceil in tlie fainih- Cypridinidae. In 

 n lat(>r work, 1868 b, [>. 358 the same author makes this genus, together with the genus 



