THE TERTIARY FORMATION. 9 



discoveries in the anatomy and habits of these animals, and describes seventeen species 

 of Cypris, nearly all of which are new, also three Cytheres (two of them new), and a 

 new genus {Paradoxostoma), from the coast of Madeira, differing from Cythere 1 in 

 having its masticatory organs blended together in a conical mass. Lastly he notices 

 a new species of Aster ope (=Cypridina). 



Including the new generic divisions established by Liljeborg and Zenker, together 

 with the sub-genera proposed for the various fossil and recent forms referable to 

 Cythere, the family Cypridce will stand thus : 



Fam. — CYPRiDiE, Dana. 



Sub-family CYPRINiE, Dana. 

 Genus Cypris, Miiller. 

 Sub-genus Cypria, Zenker. 



Genus Cyprois, Zenker. "i Probably 



,, Notodromas, Liljeborg. j the same. 



,, Cakdona, Baird. 



Sub-gen, [(] Cyprideis, 2 Jones. 

 ,, [?] Cypridea, 3 Bosquet. 



Sub-family CYTHERIN^E, Ban,,. 

 Genus Cythere, 4 Miiller. 

 Sub-genus Cythereis, Jones. 



,, Cytheridea, 5 Bosque l . 

 ,, Cytherideis, Jones. 

 ,, Bairdia, 6 M'Coy. 

 " PJ Cytherella, 7 Jones. 

 Genus [?] Paradoxostoma, Fischer. 



I may here mention that Cypretta and Cypridella, of M. De Koninck, probably 

 belong to a different group of the Entomostraca, — that Bosquet's " Cyprellae " of the 

 Cretaceous and Tertiary deposits are true Cypridince, — and that De Koninck's 

 " Cypridina" (of the Carboniferous Limestone) is not the Cypridina of Milne Edwards. 

 In a courteous reply to an inquiry with which I lately troubled M. Milne Edwards, he 

 kindly informed me that the Cypridina described in the ' Hist. Nat. des Crust.' has 

 really the an tero- ventral notch so characteristic of the genus. 



1 It resembles in carapace C. variabilis of Baird. 



2 Having lately again endeavoured to obtain clearer anatomical characters from the few dried specimens 

 I possess of this form, I find that the upper antennae are plumeless, as well as the lower pair (see fig. 2, 

 p. 16) ; and the fragmentary posterior limbs appear to be referable to more than two pairs of feet. Under 

 these circumstances we have indications of a fresh or brackish water Cythere. (Oct. 1856.) 



3 Proposed by M. Bosquet as a genus for the "Cyprides" of the Wealden and Purbeck deposits 

 (' Descript. Entom. Tert.,' p. 48) ; their thick and often tuberculated valves have some analogy with those 

 of Cyprideis. 



4 Zenker observes that Cythere is perhaps divisible into two genera at least, by the distinctive charac- 

 ters of the spermatozoa; but further anatomical research is required on this point. 



5 Proposed as a genus by M. Bosquet. 6 Proposed as a genus by Mr. M'Coy. 



7 This division is more likely to prove to be a true "genus," when the recent animal is examined, 

 than either of the other fossil forms here indicated as sub-genera ; for it presents a wider departure from 

 the type of carapace of Cythere than any of the others, and intermediate forms appear to be wanting: in its 

 system of " lucid spots " also it differs from Cythere ; approaching Cypridina in this respect. 



