studies on marine Ostracods 177 



endites) than the former; the distal and the medial bristles generally are of different types. 

 Distally on the posterior edge the protopodite has a reduced epipodial appendage, 

 generally represented only by a smaU number of short bristles. E x o p o d i t e: The proximal 

 joint is comparatively short, well defined both from the protopodite and from the distal exopodite 

 joint; it is armed on the anterior edge with a powerful endite, most frequently of about the same 

 type as the distal endite of the protopodite. The distal exopodite joint varies somewhat in shape 

 and size; furnished with a varying number of bristles along the ventral edge; of these bristles the 

 posterior-distal ones are most often of a type differing somewhat from the rest inasmuch as they 

 are densely plumose along almost their whole length. Sometimes this joint has a trace of an endite 

 on the anterior edge; most frequently, however, it is quite without anything of this sort. The 

 bristles of this limb seem to be subject to a somewhat greater variation than the bristles on the 

 preceding limbs. 



For the differences in the interpretation of the various parts of this limb in preceding 

 authors and in the present work see p. 47 above. 



Seventh limb: — Without or with rather weak sexual dimorphism. — Armed 

 distally with an unpaired comb, which is comparatively constant in type, is placed longitu- 

 dinally, is more or less horse-shoe shaped and most frequently rather powerful; when the limb 

 is held in its natural position of rest, i. e. directed upwards and curved backwards, the points 

 of the teeth of the comb are directed upwards. 



The brush-shaped organ is lacking almost throughout. 



Penis varying in type. 



The upper lip varies in size and type, with a glandular field of varying size. 



Gills are exceedingly seldom developed; situated dorsally at the back of the body. 



Special terminology: — Mandible: — The two bristles situated dorso-distally on the 

 basale are simply called: ,,the dorso-distal bristles". 



Fifth limb: — The large tooth on the first exopodite joint, composed of several 

 teeth placed in a row, is called ,,the main tooth". 



Sixth limb: ^ Of the bristles of the endites the distal ones (distal-proximal is 

 measured from the top of the endite to its base) are called „distal bristles", those placed 

 medially, often somewhat proximally to the former, „medial bristles". 



Remarks: — I have had some doubt as to which of the two sub-families Cypridiiwiae y antral arrange- 

 and Philomedmae should be placed first. In other words, which of these two groups is to "'«"' »/ ''^ "'" 



sub-famtliirs. 



be regarded as the most primitive? 



It is certainly true that in several respects the sub-family PhilotnedincLe is probably 



more primitive than the sub-family Cypridininae. Among its primitive characters may be 



mentioned : 



the absence of suctorial organs on the end bristles of the male's first antenna, 

 the differentiation of the endopodite of the second antenna iji the male into an organ 

 for seizing the female, 



Zoolo;. bidraj, Uppsalij. Suppl.-B(J. J. 23 



