all species, is ilhistrnlcd l»\' llif tullowiiit; tiijiircs (laki'ii fnim mc.isurciiicnts of {'fipridina 

 iDolitrin) leris. s): 



Pr. 1 i;^; Pr. 11 Zi '^"tl- i li J'^'^i- II •!;!: J^^'k^- '" '. 

 Protopodite: Cdxnle: Tlie endite is always well dev('lci|M'(| in hotli males and 

 females, simple or usually \\eid<ly bifiurated distally, sometimes, as. lor instance in the genus 

 Crossaphorm, even rather deeply bifurcated*; it i-; fitted with a vaiving, generally very large, 

 number of smooth spines, varying in strength and nianniT dI arrangement; in the cases when 

 it is bifurcated distally the two distal points are almost always aiin('(i with lateral spines. 

 [Exception among the species seen by me: Monopia (Ci/pridinode.s) acuminata\. Dorsally at the 

 base of the endite there is, in addition, (always?; observed in all the species of this sub-family de- 

 scribed in this treatise) a single, short bristle. Apart from this this joint seems always to be 

 entirelv without bristles (with the exception of the genus Crossophorus, see G. S. BRADY, 1880, 

 pi. XXW'lli. tig. 6). Basale: The bristles on this joint are certainly subject to variation both 

 as to their number and development, but, as far as I have found, the variation is, in most forms, 

 rather insignificant. Along the ventral side of the joint the bristles are comparatively few in 

 number, usually about six to nine, in exceptional cases, as, for instance, in the genus Crosso- 

 phorus, somewhat more. The situation of these bristles in the species examined by me was 

 pretty constant and as follows: One group is placed in the proximo-ventral corner of the joint, 

 somewhat medially; somewhat distally of this group and somewhat laterally, there is often a 

 single bristle; a little pro.xiraally of the middle of the joint there are a couple of bristles and some- 

 what distally of this point a couple more. Dorsally this joint seems in most cases to have only 

 three bristles, viz. the two dorso-distal bristles which are, as is pointed out above, characteristic 

 of the whole family and another one, placed about at the middle of the joint or a little in front 

 of this point. In the genus Crossophorus, however, the latter bristle is replaced by a whole 

 series of rather long and powerful bristles. E x o p o d i t e: Most frequently about as long 

 as or very slightly shorter or longer than the anterior side of the first endopodite joint; it is 

 drawn out to a rather fine point and has dorso-distally a sort of cushion of rather short, exceedingly 

 fine hairs placed closely together in a ring (exits of the glandular cells). Endopodite: 



'^ In a numbpr of form.s, in which this endite is only weaiily bifurcated, for instance in Cypridina (Cypridina) 

 serrain van. ajfirmans (cf. l)elow, fig. 9 of this form), there is lielween the two distal points a more or less well- 

 developed spine-shaped or verruciform process. In other forms, in which this endite is more deeply bifurcated, this proc( ss 

 is entirely absent. To judge from its situation, this process may possibly be interpreted as the original point of the 

 endite. The two comparatively powerful points on each side of the process in question would according to this point 

 of view be considered as having presumably arisen by two of the distal spines witli which the endite is more or less copiously 

 furnished having developed more powerfully than the others. According to this oj)inion this endite originally would 

 have been characterized by a simple point in this group of animals. 



There are also, however, facts that seem to argue against this interjirctation. First this endite is deeply 

 bifurcated in Philomedinae, Sarsiellidae and Asleropidae, thus in all the remaining groups of Cypridiniformes in which 

 it is developed, and secondly it is most deeply bifurcated (about the same as in Philomedinae) in that genus of the 

 sub-family Cypridininae (Crossophorus) which we have rather strong reasons to regard as the most primitive. An 

 additional argument against the assumption that the two distal points are to be regarded as a couple of spines seems to 

 rae to lie in the fact that these points, even in species in which they are comparatively weakly developed, are almost 

 always armed with secondary spines contrary to the other spines of this endite whicli are all perfectly smooth (exception: 

 Monopia (Cypridinodes) acuminata). 



It may, however, be impossible at present to decide with certainty which of these two alternatives is the correct one. 



