114 



POST-TERTIARY ENTOMOSTRACA. 







TEXTURE AND MARKINGS OF 







SHAPE AS SEEN LATERALLY. 



SHELL. 



HINGEMENT. 



CVTHERIDiE — 









Paradoxostoma 



Elongated, compressed, usually 



Thin, fragile, polished, and de- 



Simple. 





higher behind than in front ; 



void of sculpture, but often 







usually subovate, subtriangular, 



marked with arborescent co- 







or flexuous 



loured patches of black, olive, 

 or violet hue 





CvPRIDINADiE — 









Cypridina 



Subcircular or very broad oval, 

 with a distinct beak and notch 

 in front and a slight projection 

 behind 



Smooth, thin, and flexible 



Nearly simple. 



Bradycinetus ... 



Similar to the foregoing, beak and 

 notch well developed 



Dense, punctate 



Nearly simple. 



Philomedes 



Similar to the above, posterior 



Moderately strong, punctate, or 



Nearly simple. 





extremity usually with one or 



foveate and ribbed 







two spines 







Asterope 



Elongated, beak not at all pro- 

 duced, posterior extremity 

 evenly rounded 



Moderately strong, smooth 



Nearly simple. 



Eurypylus 



Beak obsolete, no distinct notch ; 

 seen from above widest in 

 front 



Robust, more or less pitted 



— 



POLYCOPID^ — 









Polycope 



Circular or nearly so, no notch or 

 beak 



Thin, calcareous, smooth, punc- 

 tate, or reticulate 



Formed by a slight overlapping of the 

 valves. 





Cytherellid^— 









Cytherella 



Usually elliptical, compressed, 



Thick and dense, smooth or 



A groove on the right valve into which 





valves very unequal, the right 



variously sculptured 



the edge of the left is received. 





much the larger 







Bosquetia 



Obliquely and broadly ovate, right 



Very thick and hard, smooth 



Formed by an overlapping (?) of the 





valve much larger than left, and 





right valve at each extremity. 





overlapping both above and 









below 







