SLiidios on niarino Oslracods 



81 



liomologous with tlie exopodite, but with an epipodial appendage, au explanation that is. 

 by the way, also supported by the function of this organ. 



On this, as on the following, limbs, the endites are numbered proximally distalh*. 



Maxilla: — The morphological interpretation of the different parts of this limb 

 presents considerably greater difficulty than an explanation of the second antenna and the 

 mandible, a fact that is clearly reflected in the preceding literature. A detailed study of the 

 different types of maxillae in Polycofidae and a comparison between the state of affairs in 

 this family and in other groups ought, however, to render possible a solution of this problem 

 that, if not absolutely certain, is nevertheless fairly certain. 



The maxilla of Polycofsis serrata G. W. MULLER (cf. G. W. MUllek, 1894, pi. 7. 

 fig. 51 ^reproduced in %. Ill: 1 of the present treatise) represents the simplest type within 

 the family Polycopidae; it maj^ be described as a rather straight, typically biramous limb, 

 presumably of a fairly primitive type. Its protopoilite, which Ss fairly strong, consists of two 

 well developed joints, coxale and basale, proxinially of which there is a somewhat weaker 

 joint, the procoxale. The exopodite and the endopodite, both of which are situated distally 

 on the basale, the former weakly two-jointed, the latter distinctly threejointed, are also fairly 

 well developed; the former is somewhat weaker than the latter. The protopodite has on the 

 procoxale and the coxale slight indications of three endites armed with bristles; there are 

 some ventral bristles on the basale as well. No epipodial appendage is developed. In other 

 forms of this family, e. g. Polycope rostrata (i. W. MOller and P. tuhernsa G. W. MOller, 

 the maxilla differs from the preceding type by having the basale, the endopodite and the 

 exopodite bent ventrally and by an increase in the strength of the three endites on the 

 procoxale and the coxale; the basale, on the other hand, has no endites. In both these 

 species the exopodite show's no division into joints; in the former one the endopodite is still 

 distinctly three-jointed, while in the latter this branch too is unjointed; in these species too, as 

 in all the others belonging to this family, the maxilla has no epipodial appendage. Cf. G. ^^^ 

 MOller, 1894, pi. 7, %. 13 (reproduced in fig. Ill: 2 of this treatise) and fig. 27. 



The maxilla found in the families Cypridinid-ae (in the scope given to this family in the 

 present work) and Sarsiellidae (i. e. in all the Gyp rid in ids except the families Rtilidermalulae 

 and Asteropidae) shows a type that agrees rather strikingly with the maxilla of Polycope 

 rostrata and P. tuberosa (see flg. Ill: 3). The morphological explanation of this limb in these 

 families, which is given in the present work on the basis of a comparison with these two species, 

 may accordingly be considered as fairly well grounded. In these two families the protopodite 

 of the maxilla is strongly developed and is more or less distinctly divided into joints; iji 

 most cases two well developed joints, coxale and basale, can be observed, proximally of which 

 a third joint, the procoxale, is sometimes marked off. The procoxale and the coxale are 

 (at least in all the species I have investigated or in which I was able to ascertain the conditions 

 with the help of the literature — except in the genus Pseudophilomedes) armed with three 

 endites; these endites are in most cases very strongly developed, considerably more strongly 

 than in the two last -mentioned P o 1 y c o p i d s; the basale, on the other hand, has no 

 trace of anv endites. The basale has two appendages distally. which are certainly to ho 



Maxilln. 



Pulifrnpttinc. 



('i/prnliiuilne anil 

 Snrsiellifliic. 



