78 



donne lieu de croire que cle nouvelles recherches et 

 cle nouvelles observations, prouveront qu'il n'est pas 

 strictement vrai qu'en France, en Angleterre, en 

 Russie, il n'existe point de trilobites entierement prives 

 d'yeux, comme le dit le savant auteur que je viens 

 de citer." See Annales des Sciences Naturelles, 

 Vol. 8. page 195* 



GENUS DIPLEURA. Green. 



Body, contractile, not much depressed, and slightly 

 tapering. 



Buckler, pustulous, trilobate, cheeks protuberant, 

 with oblique, annular, oculiferous tubercles. 



Abdomen, with fourteen arliculations, not lobate, 

 the ribs double. 



Tail) suborbicular, not so large as the buckler, co- 

 vered with an epidermis. 



This genus derives its name from two Greek words, 

 which signify double ribsj many of the trilobites are 

 thus characterized; but in no species, is this organi- 

 zation so remarkable as in those which belong to the 

 Genus Dipleura. The expansion of the tail resem- 

 bles, in some degree, that of the Isotelus, but other 

 obvious characters sufficiently distinguish it from 

 that interesting genus. The fossils arranged under 

 this section are larger than most other trilobites. 



