4 CARBONIFEROUS ENTOMOSTRACA. 



" Shell smooth, thin, and flexible ; notch shallow ; its posterior extremity only slightly 

 exserted" (Brady, 'Proc. Zool. Soc.,' 1871, p. 291). Looking at the series of recog- 

 nized Cypridince, we are inclined to think that there are two leading forms of carapace : 

 1. The elongate-pyriform, such as C. Meynaudii, C. elongata, and C. Bairdii ; and, 2, 

 the oval-oblong, such as C. Norvegica and C. Japonica. 



2. PfliLOMEDES, Lilljehorg. 



"Valves elongated, thin; notch broad; anterior extremity obtuse" (Brady, p. 462). 

 "Shell of moderate strength and density" (Brady, *Proc. Zool. Soc.,' 1871, p. 291). 



3. AsTEROPE,^ Philippi. 



"Shell elongated, fusiform, or subcylindrical ; beak rounded, not at all produced" 

 (Brady, * Trans. Lin. Soc.,' vol. xxvi, p. 464 ; Cylindroleheris and Asterope, ' Proc, Zool. 

 Soc.,' 1871, p. 292). This genus appears to be one of the most consistent in form and 

 structure of carapace. 



4. Bradycinetus, G. 0. Sars. 



" Shell thicker and more compact than in the preceding genera {Jsierope and F/iilo- 

 medes) ; notch deep, with setose margins " (Brady, ' Trans. Lin. Soc.,' xxvi, p. 466). 

 " Shell much denser than in CypridincB, punctate ; notch deep " (Brady, ' Proc. Zool. 

 Soc.,' 18 71, p. 291). 



5. Edrypylus, G. S. Brady. ^ 



"Valves hard, calcareous ; closely pitted on the surface, without a notch. Carapace 

 rounded (oval) on side view ; anterior end slightly produced, with a short blunt beak ; 

 posterior rounded ; seen from above clavate, broadly rounded in front, and attenuate 

 behind" (Brady, 'Les Ponds de laMer,' 1869, p. 141). Though little is known of the 

 soft parts, Mr. Brady is satisfied that Eurypyhs is a Cypridinad. 



^ Mr. Brady thinks that this genus might with propriety be made the type of a distinct family. 



