6 



CARBONIFEROUS ENTOMOSTRACA. 



III. Cladocopa, having the Polycopidm only. — " The type of this group is Polycope, 

 a genus recently described by G. O. Sars, which occurs on some parts of the coasts of 

 the British Islands and Norway, and in the Mediterranean " (Brady, ' Trans. Lin. Soc.,' 

 xxvi, p. 356). 



1. Polycopid(B. — " Valves subequal, thin, not notched in front " (Brady, op. cit., 

 p. 470). 



PoLYCOPE, G. 0. Sars. 



" Valves rounded, ventricose, thin, and fragile, corneo-calcareous " (Brady, op. cit., 

 p. 470). 



IV. Platycopa, having the Cytlierellidce only. — "This group is typified by the 

 genus Cytherella, known, before Sars's researches, only from fossil specimens " (Brady, 

 op. cit., p. 317). 



1 . Cytherellidce. — " Valves unequal, very thick and calcareous, not notched in 

 front " (Brady, op. cit., p. 472). 



Cytherella {Jones), Bosquet. 



" Valves elongated, flattened, thick and hard, very unequal ; the right much larger 

 than the left, and overlapping throughout the whole circumference, presenting round the 

 entire inner margin a distinct groove, into which the valve of the opposite side is received " 

 (Brady, op. cit., p. 472). 



The following Synopsis of existing Genera and Species will aid the student in his 

 search through the somewhat scattered bibliography of those recent Ostracoda which are 

 concerned with the present Part of our Monograph. 



