29 



Fam. Polycopidae. 



Characters of the family. Shell of more or less rounded shape, with 

 the valves subequal and wanting any obvious clothing of hairs. Anterior an- 

 tennae very movably connected with the body and of somewhat varying structure, 

 but always tipped with a fascicle of long natatory setae. Posterior antennae 

 with the basal part rather thick and muscular, though less so than in the 

 Myodocopa, rami not very unequal in size and both provided with long nata- 

 tory setae. Anterior lip comparatively small. Mandibles with the body well 

 defined and the masticatory part abruptly incurved, palp only composed of 2 

 distinctly defined lamellar joint, the proximal one carrying at the end anteriorly 

 a small exopodal appendage. Maxillae with the basal part divided into 2 seg- 

 ments, the 1st provided inside with a well defined masticatory lobe, the 2nd 

 with 2 much smaller setiferous lobes; terminal part, constituting the palp, 

 large and compressed, being divided at the end into 2 deflexed rami, the inner 

 3-articulate and clothed inside with numerous recurved, partly spiniform setae, 

 outer ramus much narrower, and not distinctly articulated, but tipped with a 

 dense fascicle of natatory setae. Maxillipeds lamellar in structure and each divided 

 into 3 more or less distinctly defined segments rapidly diminishing in size, the 1st 

 rather large and provided outside with a well developed semilunar vibratory plate, 

 2nd segment subtriangular in shape, with a small setiferous lobe at the end out- 

 side, last joint very small and in some case not distinctly defined. None of the 

 limbs transformed in male. Caudal lamellae with the claws inserted within more 

 or less deep incisions of the margin, left lamella in male more or less conspicu- 

 ously transformed and contributing to the formation of the very complicated 

 and pronouncedly asymmetrical copulatory apparatus. 



Remarks, This family was proposed by the present author for the reception 

 of the genus Poly cope, the only one at first known. In the year 1894 another 

 genus, Polycopsis, referable to the same family, was added by G. W. Miiller, 

 and I regard it as very probable, that the number of genera will be still more 

 increased in future. Both of the above mentioned genera are represented in 

 the Fauna of Norway. 



Gen. 1. Polycope, G. O. Sars, 1865. 



Generic Characters. Shell, as seen laterally, more or less perfectly orbic- 

 ular in shape, with the 2 extremities very little dissimilar, the anterior one 

 being however in most cases somewhat more bowed in the middle than the 



