lOU TAGE SK0G8BERG 



for Podoco'pa than to that of C y p r i d i n i d s and P o 1 y c o p i d s. — In his work of 1912 

 G. W. MULLER does not mention this limb in the diagnosis of Myodocopa, a fact that seems to 

 indicate that he has arrived at the same opinion about the classificatory value of this organ as 

 that adopted in the present treatise. 

 ■'/""/'"• Maxilla: — With regard to this limb it may be said that it shows less difference 



in Myodocopa and Podocopa than one would be inclined to believe from G. W. MtJLLER's 

 statements. In Polycopidae, especially in a number of forms belonging to this family, we find 

 a maxilla of so simple a type that from it we can quite naturally derive the types found in other 

 families. In most of the forms belonging both to Myodocopa and Podocopa the protopodite is 

 armed with three endites, in most cases powerful (in the H a 1 o c y p r i d s two of these are, 

 however, almost completely joined). In almost all recent Ostracods the endopodite of 

 this limb has two or three joints: the number of joints varies, however, somewhat, both in 

 Myodocopa and Podocopa. The most important difference according to G. \\. MULLER would 

 undoubtedly be that in Podocopa the exopodite is developed as a vibratory plate, while in 

 Myodocopa this limb has no such organ. In this matter G. W. MtJLLBR is, however, probably 

 quite mistaken; see p. 34 above. 

 Fijth iimh. Fifth limb: — As has been shown on p. 85 above, this appendage appears in very 



different types in the recent Ostracods. The type found in the Halo cyp rids differs very 

 much from both the Cypridinids and the P o 1 y c o p i d s, and has a striking resem- 

 blance, on the other hand, to the fundamental type in Podocopa. We must note, however, 

 that, according to G. W. Muller, the Halocyprids are to be regarded as primitive 

 with regard to this limb, an assmnption which, although not at all proved, cannot, as we 

 have seen above, by any means be considered impossible. The Myodocopa would be characterized 

 by a powerful vibratory plate on this limb. This character is, however, of slight significance. 

 In the first place the vibratory plate is of rather moderate size in the Halocyprids; 

 secondly we also find a rather powerful vibratory plate on this limb in forms belonging to 

 Podocopa, e. g. a few C y p r i d s, all N e s i d e i d s and Cytherellids. 

 Sixth Umh. Sixth limb: — This limb is absent in Polycopidae and apparently also in the 



females of the genus Cytherella. In Halocyprids and Cypridinids it appears in 

 very different types; the type found in the former group shows a far-reaching agreement 

 with the fimdamental type in Podocopa. In the males of the Cytherellids we find a 

 type that differs very much from both Halocyprids, Cypridinids and other 

 Ostracods. G. W. MOller considers this limb of the Halocyprids to be of a 

 primitive type. 

 Seventh Umh. Seventh limb:— This appendage is absent in both Polycopidae and Cytherellidae. 



In other forms it varies fairly considerably, but it may also be said of this limb — though 

 with a certain amoimt of reserve — that in the H a 1 o c y p r i d s it shows a greater agree- 

 ment with Podocopa than vyith the Cypridinids. 

 Bmsh-shapcd organ. Brush-shaped organ: — This organ is found both in Myodocopa and Podocopa. 



It is presumably of a comparatively slight classificatory value as it probably existed, as 

 G. W. MOller has pointed out, even in tlie P in t o s t r a c o d s. 



