L>8 



edges smooth, inner duplicatures very large, especially at the 

 anterior part. Natatory setae of lower antennae not reach- 

 ing beyond the terminal claws. Palpus of 1st pair of 

 maxillae very narrow, cylindrical, last joint small, masticatory 

 lobes long and narrow. Caudal rami rather large, more or less 

 lamelliform, dorsal edges sometimes pectinate, claws very unequal 

 both coarsely denticulate, seta of dorsal edge absent or very 

 small, the apical one rather elongate. Propagation exclusively 

 parthenogenetical. 



Bemarks. — I have felt justified in establishing this new 

 genus for reception of a few species of the old genus Cypris, 

 which differ in some points rather markedly from the more typical 

 forms, both as to the shell and the animal. The very narrow 

 and elongate shape of the shell may be named as an easily 

 perceptible outer character, which has also given rise to the 

 generic appellation. Besides, the unusually large inner duplica- 

 tures of the valves at their anterior extremity are rather charac- 

 teristic. As distinctive anatomical characters may be mentioned 

 the comparatively feebler development of the natatory setae on 

 the antennae, the narrow elongate form of the palpus and 

 masticatory lobes of the 1st pair of maxillae, finally the form 

 and armature of the caudal rami. In addition to the species 

 described below, the northern form, Cypris fasciata Mtiller, 

 undoubtedly belongs to the same generic type, and a rather 

 nearly related species I have succeded in raising from dried 

 Chinese mud. It may also be, that some others of the exotic 

 forms, described by Baird and Brady, may belong to the same 

 genus. 



3. Stenocypris malcolmsonii, (Brady). 



( p l- I, fig- 7, 8; PI. V, fig. 1-4). 



Cypris cylindrica, Baird, 1. c. Proceedings Zool. Soc. London 

 1859, p. 233. PI. 63, figs 3, 4 (not Sowerby). 



