334 Prof. T. Rupert Jones on the 



the terra ^^ Cypridina''^ was applied to various fo?3ils,a3 referred 

 to above. The greater number of these misnamed fossils 

 belong" to Gi/there, some to Entomis^^ others to Gypridella 

 and Ct/prella, and even to Isocldlma and Leperditia. On 

 the other hand, other fossils, more truly Cypridinal in cha- 

 racter (.sucli as Bosquet's Gi/preUce from the Cretaceous and 

 Tertiary beds of Holland and Belgium), being possessed of 

 the anterior notch and beak, were regarded as distinct on that 

 account, and thus misunderstood. 



One of the best authorities on the biology of this group of 

 lowly Crustacea, Dr. G. S. Brady, F.R.S., has given the 

 following interesting statement about them : — 



" The Cypridinidse, owing to their considerable size and 

 frequent capture in the surface-net, have attracted more 

 general attention from zoologists than any other division of 

 the Ostracoda ; but, compared with the Cypridte and Cythe- 

 ridse, the number both of species and individuals is very 

 small. They appear to be most abundant in the warm 

 surface-waters of the tropical seas, contributing largely to 

 the phosphorescence of those regions. The males only (at 

 any rate of those species which have been thoroughly ex- 

 amined) are endowed with swimming power, the females 

 being non-natatory and passing their lives wholly at the 

 bottom, a condition imposed upon them by the absence of the 

 tuft of long filaments, attached to the first pair of antennas, 

 which is characteristic of the males. The shape of the shell, 

 too, is usually very different in the two sexes, the male being 

 very long and slender in comparison with the female. 



'' Judging from the number of fossil species belonging to 

 titis family which have been found in the Coal-measures and 

 other Palaeozoic formations, we must suppose that the Cypri- 

 dinidge were much more abundant in old times than now. So 

 we may perhaps likewise infer that they were chiefly inhabi- 

 tants of shallow warm water, possibly of brackish and estua- 

 rine localities." 



The abundance of Cypridinids in some beds of the 

 Carboniferous or Mountain Limestone, which was formed in 

 an open sea, indicates, however, that these bivalved Crusta- 

 ceans were not confined to littoral areas f. 



" Some few species have been described from Cretaceous 

 and Tertiary strata ; but it would appear that the group 

 attained the greatest development in the Carboniferous era, 



* Particularly in the case of the so-called " Cypridinen-Schiefer " of 

 Germany. 



t Some remarks on the fossil forms and their relationships were given 

 in the ' Monthly Microscopical Journal/ vol. x. (1873) pp. 71-7(3. 



