140 



PANAMIC DEEP SEA ECHINI. 



the genital plates are ankylosed in one, and distinct in the other. The 

 bivium is separated from the trivium by the posterior interambulacra, as 



Figs. 202. 202 a . 20:?. Pourtalesia miranda. 



is the case in P. Jefireysi, P. laguncula, P. Tanneri, and P. eeratopi/ga. 

 The ocular plates can be traced in the posterior ambulacra, Fig. 205. 



Seen from the actinal side the labium and the sternum are separated by 

 the anterior row of the posterior ambulacra, Figs. 203, 204, and by the pos- 



18 mm. 

 Fig. 204. P. miranda. 



18 mm. 

 FlG. 20"). P. MIRANDA. 



terior ambulacra which unite on the median line, as in P. Jcffreysi and the 

 species named above. The labium of P. miranda is, like that of P. laguncula 

 and P. Tanneri, in contact with the actinostome, Figs. 203, 204, and the pri- 



