376 TAGE SKOCSniORO 



posterior one being placed ratlier more inward. The second endite in these species has seven 

 to nine, the third eleven to thirteen bristles; some of these bristles are situated very close 

 together, not arranged in a row (in the accompanying figure these endites are rather strongly 

 compressed). Distally on its outer edge the jjrotopodite has no chitinous spine, contrary to most 

 forms of the sub-family Cypridininae. The epipodial jilate has an. indication, though 

 only a faint one, of the ear-like shape that is characteristic of the family Asteropidae. On its 

 marginal bristles the long hairs continue right out or almost right out to the points; 

 the points of these bristles are not modified to function as sensory organs. This appendage 

 finishes dorsally with an irregular, powerful, spine-like chitinous swelling. The exopodite 

 always seems to have four joints. The jjroximal joint is rather small and weak (cf. fig. 21 of 

 Ph. (Scl.) Afpelldfi). The main tooth, which is fixed obliquely-transversaUy, is developed some- 

 what less strongly than in the sub-family Cypridininae and does not seem to play so important 

 a jjart in breaking up the food as it does in the sub-family mentioned. It seems to be subject 

 to rather slight variation. In aU the .species investigated by me four constituent teeth were 

 observed; the anterior one of these is longest and most powerful, the others decrease greatly 

 in length and strength the more posteriorly they are situated, the most posterior one often 

 being very small and weak and may even, in very exceptional cases, be quite missing. The 

 constituent teeth are often slightly bent backwards, sometimes almost straight, and are furnished 

 on their posterior edge with irregular teeth which vary in form and number. The anterior, 

 strongest, constituent tooth has proximally on the inside a powerful irregular tooth-shaped 

 protuberance. On all the species of this genus that I investigated there is a single bristle on the 

 posterior side of this joint, close to the main tooth, and three bristles on the anterior side of 

 the joint, two of which are situated close to the main tooth and the third farther out on the 

 joint (cf. fig. 21 of Ph. (Scl.) Appellofi). — These four bristles seem certainly to be homologous 

 with the similarly situated four bristles that were observed in the majority of the forms belonging 

 to the sub-family Cypridininae that I have investigated. — The second exopodite joint, on the 

 other hand, is rather large, exceedingly strongly chitinized and differentiated on the inside to 

 a powerful, tooth-like, almost triangular process. This process is weakly bent inwards and back- 

 wards, in other words in the same direction as the constituent teeth of the main tooth on the 

 preceding joint. In the species investigated by me this process is furnished on the inner edge 

 near the base with a few rather weak, irregular secondary teeth; on the outside it has a rather 

 powerful, conically rounded, smooth secondary tooth directed obliquely outwards and forwards; 

 apart from this it is quite smooth. This tooth-like joint is certainly the most important masti- 

 catory organ of the limb. With the differentiation of the joint itself to the most important 

 masticatory organ a parallel reduction of the bristles on this joint seems to have taken place. 

 In all the species of this genus tJiat were investigated by me only five bristles were observed 

 on this joint; four of these bristles were situated on the posterior side of the large inner tooth-like 

 process, three in one group, the fourth by itself somewhat proximally of the former ones. On 

 account of the position of these bristles in the male it seems probable that the group of tlircc 

 l)ristlcs corresponds to the important masticatory bristles in the sub-family Cypridininae called 

 tlx! a- and l)-bristlos, while the single bristle is hoiiiologous with the c-bristle in this sub-family. 



