studies on marine Ostracods 83 



at least there seem to be no facts that are definitely against it. A greater number of joints 

 do not appear in any forms; a two-jointed protopoditc and a three-jointed endopodite occur 

 in the most widely separated groups viz: Cypridinids, Halocyprids, Cyprids, 

 Nesideids, Cytherids and Cytherellids. A smaller number is found in the 

 Polycopids and in Darwinulidae. No trace of a procoxale has yet been observed in any 

 recent forms; it is, however, not quite impossible that such a joint existed originally. Nor 

 does there seem to be anything of importance to add with regard to this author's 

 assumption about the endites on this limb. A powerful endite is fovmd on the coxale in 

 almost all groups. Without drawing any conclusions from this, I wish, however, to point 

 out here that an endite or indications of such a process on the basale is foimd not only in 

 Halocyprids and Polycopids but also in Asteropids and Philomedes as 

 well, and in the Cypridinids, where traces of such an endite can also be observed, 

 these traces are most strong in forms which are presumably to be considered as primitive 

 (CrossopJiorus) ; cf. the remark on the group Cypridiniformes below. On the other hand there 

 seem to be no reasons that support the assumption that the palp in the Cypridinids 

 is of a more primitive type than in other forms because of its size. The group Polycopidae, 

 which is presumably in several respects rather primitive, is characterized by a very short mandible. 

 Might not this fact be considered to support an assumption that the elongated mandible palp 

 in Cypridinids and Halocyprids represents a secondary type? The assumption 

 of a short mandible or at any rate of a moderately long mandible as being the original one in 

 the Ostracods seems to me to be supported by the fact that in a number of forms in this 

 group the mandible has been developed as the most important crawling limb on the anterior 

 part of the body, while in others the endopodite of the second antenna has been developed for 

 this function. It seems to me that the easiest way to explain this phenomenon is by assuming 

 that in the Protostracods both the mandible and the endopodite of the second 

 antenna were relatively short. With regard to the exopodite of this limb G. W. MCller makes 

 no assumption, as has been pointed out before. In the recent Ostracods this branch is 

 always very small; in a number of forms it is peg-like, unjointed and ahnost bristleless; in 

 others it is quite absent. It seems to me fairly probable that this branch was comparatively 

 small in the Protostracods; on the other hand it seems to be more difficidt to say 

 anything certain about its type. As to whether the protopodite had an epipodial appendage 

 is very difficult to decide; it may be best to leave this question open. 



After having discussed the problem of the mandible of the Protostracods 

 G. W. MtlLLER put forward the question as to why the endopodite of the second antenna had 

 been developed into a powerful crawling leg in Cyprids, D a r w i n u 1 i d s, Nesideids, 

 Cytherids and Cytherellids; would it not have been more probable, he asks, for 

 this function to have been taken over by the mandibular palp in these groups as in the Cypri- 

 dinids? In answer to this question this author writes as follows, p. 194: „So auffallend ahnlich 

 die Verwerthung des Mandibulartasters bci den C y p r i d i n i d e n imd der 2. Antennc bei 

 den Podocopa (natiirlich abgesehen vom Schwimmen bei letzteren) ist, so existirt doch ein 

 wesentlicher Unterschied: bei den einen haben wix es mit einem GrabfuB, bei den anderen mit 



