84 



The name of this genus is derived from the remark- 

 able spinous projections from the caudal end; this 

 peculiar organization separates it widely from the 

 other genera. The Paradoxides Spinulosus of Wah- 

 lenberg, which is supposed to be the old Entomolithus 

 Pamdoxus of Linne, the fossil, with which all the tri- 

 lobites were for a long time confounded, has not 

 only projecting spines from the tail, but from all the 

 costal arches of the lateral lobes. The presence of 

 eyes or of oculiferous tubercles in the Ceraurus, would 

 alone be sufficient to separate .it from the genus to 

 which that interesting fossil belongs. In the eighth 

 volume of Annales des Sciences Naturelles, Count 

 Rasoumowsky has figured and described the frag- 

 ment of a very curious relic, which seems to be an 

 intermediate link between our genus and paradox- 

 ides; in addition to a number of filamentous elonga- 

 tions of the costal arches, a curved spine seems to 

 project from the end of the tail, as in the #. limulurus. 

 No name is given to this trilobite, which appears to 

 have been found on the banks of the Yaousa, near 

 Moscow, where it occurs in black, coarse, argillaceous 

 schistus. The Ceraurus is probably a very rare ani- 

 mal remain, as we have only met with it, in the unri- 

 valled cabinet of trilobites belonging to the Albany 

 Institute. 



CERAURUS PLEUREXANTHEMUS. Green. Cast No. 33. 

 Fig. 10. 



Clypeo postice arcuato, angulo externo in mucro- 

 nem valde producto; oculis minimis remotis, post- 



