432 TAGE SKOGSBERG 



Witli regard to the differences between the previous authors' interpretations of the 

 different parts of this limb and that which is followed in tliis work, see above pp. 33 and 36. 



Fifth limb: — This has no (or sometimes very slight?) sexual dimorphism. — Like 

 the preceding limb it has a very peculiar t}'pe of structure, very different from all other 

 s t r a c d s; see fig. IV: 5. The protopodite and the two proximal exopodite 

 joints are differentiated into a rather long, narrow, tongue-shajied and quite unjointed organ, 

 strongly compressed from the sides. This organ is bent slightly inward, — in the same way as 

 the protopodite of the maxilla, — pointing anteriorly and outwards and twisted so that its 

 ventral edge is jjointed obliquely downwards towards the maxilla. Along the ventral edge of 

 this organ there is a dense series of moderately long or more or less short bristles. The distal 

 part of the exopodite is reduced, being only represented by one or a few bristles, more 

 seldom by a small verruciform process laterally somewhat in front of the middle of the tongue- 

 shaped organ formed by the protopodite and the two proximal exopodite joints. The e p i- 

 p o d i a 1 a p p e n d a g e is supported by rather powerful chitinous lists, which end dorsally, 

 as they do ventrally, in a strong, spine-like part. The ventral one of these spines forms the 

 end, so to speak, of the tongue-like part posteriorly; it is not free, as one would be inclined 

 to believe from the descriptions of previous writers, but is attached to the wall of the body along 

 the whole of its dorsal side; cf. fig. 14 of A. aberrata. 



With regard to the differences between the interpretations of the different parts of this 

 limb that have already appeared in the literature and that accepted in the jjresent work see 

 above pp. 38 — 42. 



Sixth limb: — This has no (or sometimes very slight?) sexual dimorphism. — It is 

 always rather large and rather considerably lengthened in the longitudinal direction of the body, 

 lamelliform, quite unjointed, but in other respects it varies considerably in type. 



Seventh 1 i m b : — This has no or sometimes very slight sexual dimorphism. — - It 

 has from two to four end combs arranged in pairs. In other respects it varies considerably in t}'pe. 



Penis: — This is small and is only weakly chitinized. Distally it is split into two lobes. 



U i 1 1 s: — These have no or only very slight sexual dimorjjhism. — Contrary to what is 

 the case in all other known Ostracods* well-developed gills are foimd in this grouj). They 

 consist of a number of lamellae, attached along the dorsal side of the posterior part of the body 

 and arranged in two longitudinal rows separated by a narrow space. The lamellae are placed 

 transversely, pointing backwards and upwards and, when the animal is seen from the side, they 

 cover the greater part of the dorsal side of the back of the body. With regard to their fine 

 structiu-e they resemble the lamellae of the gills in the other closely-related Crustacean groujjs. 



S fecial terminology: — First antenna: — The far-reaching resemblance shown 

 by the end bristles, with regard to tlieir number, position and type, to the end bristles on 

 this limb in the family Cyfridinidae can only be explained as real homology; on account of 

 tliis I considered it best to make use of the same notation for this group as for the family 

 just mentioned (cf. loniark on genus Asteropc, p. 462). 



* Cypridiiiit H tl'^iiitlnrji. (;. W. Mli.lf.I!, IH'.IO, ].. Ji'8 i.s an cXi rplidn. 



