206 Messrs. Austin on new Genera 



Genus Astrocrinites, Austin. 



Def. — Dorso-central plate quadrangular, to which four pairs 



of elongated plates are attached, imparting a lobed shape to 



the fossil. In the retiring angles at the base of the four lobes 



are a like number of ambulacra. Mouth central. Anus lateral. 



A. tetragonus, Austin. 

 Def, — The plates of this species agree with the generic de- 

 finition. Each of the elongated plates has two or three rows 

 of minute tubercles around its outer margin, apparently for 

 the attachment of spines. The ambulacra have each a double 

 row of pores placed centrally, with marginal tubercles. Near 

 the centre of the dorso-central plate is an oval eminence, ap- 

 parently analogous to the madreporiform tubercle on the dorsal 

 surface of the true Starfishes. 



Genus Sycocrinites*, Austin. 

 Def. — Dorso-central plates three, forming a pentagon. First 

 series of perisomic plates five, on which rest other series of 

 plates, answering, though larger in proportion, to the abdo- 

 minal (pectoral) plates of those Crinites which possess rays. 

 Mouth central, anal pore lateral. Column unknown. 



S. clausus, Austin. 

 Def — Dorso-central plates three ; perisomic plates five, on 

 which rest a second series of five plates which answer to the 

 interscapular plates of those Crinites possessing rays ; a third 

 series of five plates close in the apex, excepting a minute cen- 

 tral opening which is considered to be the mouth, and which 

 was probably valvate. The anus is situated laterally at a point 

 between the first and second series of plates. Column un- 

 known. 



S. Jacksoni, Austin. 



Def — Dorso-central plates three, forming a pentagon. Pe- 

 risomic plates five. Apex closed in by five plates. Mouth 

 central and valvate, anal pore lateral. Columnar attachment 

 small. Column unknown. 



S. anapeptamenus, Austin. 

 Def — Dorso-central plates three, forming a pentagon. First 

 series : perisomic plates five, all hexagons. The second series 

 of plates arch over the apex, leaving a central opening which 

 was probably protected by a plated integument. Anal pore 

 lateral and projecting. Column unknown. 



* From su/con, a fig. 



