196 PEor. p. M. DUif can's revision or the 



Ambulacra flush, apetalous ; poriferous zones uniporous ; pores 

 in small plates near the peristome and crowded there, producing 

 rudimentary phyllodes between slight bourrelets. 



Peristome beneath the apical system, and slightly in front of 

 the centre, depressed, indistinctly pentagonal. Posterior inter- 

 radium slightly ridged and sinking gradually to the depressed 

 truncation, which is occupied by the large marginal periproct, 

 which is oval and plated with scales ; an anal tube may exist. 



Interradial plates large. Tubercles small and numerous, 

 largest actinally, many on the bourrelets. Spines straight, not 

 long, slender, smallest with a tip of pointed tubercles. Pedicel- 

 larijB long and short, tridaetyle, mostly blunt. Spheridia large, 

 numerous, naked. 



Becent. Mouth of English Channel, and Caribbean Sea, 230- 

 600 fathoms. 



III. Family CoiiLTRiTiDJS. 



Exocyclic nodostomes with apical systems disconnected and 

 either elongate or eubcompact. Ambulacra similar ; bivium 

 widely separated from the trivium ; floscelle absent. 



Genus Collyrites. 

 Dysaster, 

 Hyboclypeus. 

 Infraclypeus. 

 Grasia, 



Genus Collteites, Des Moulins, 1835, Etudes s. lea Echin. 

 p. 46. Loven, 1874, Etudes, figs. 55-60, 98, 180. 



Syn. Dysaster, Agass. (pars). 



Test moderate and rather large, ovoid, oblong or cordiform in 

 marginal outline, tumid, moderately high abactinally, depressed 

 there or raised anteriorly, more or less narrow^ly truncated pos- 

 teriorly, actinally flat, or irregularly swollen or concave. 



Apical system elongate and dislocated; an anterior portion 

 consisting of a small anterior radial plate and of the antero-lateral 

 basal plates, separated from the posterior basal plates by the 

 united antero-lateral radial plates ; the posterior portion consisting 

 only of the united postero-lateral radial plates. The portions 

 are widely separated by numerous small plates belonging to the 

 postero-lateral interradia ; the madreporite in the right anterior 

 basal plate. 



