CHARACTERISTIC DEEP-SEA TYPES. — CRICOIDS. 117 





Fig. 404. — Metacrinus angulatus. \. (Carpenter.) 



ferences existing between the liassic and 

 the modern Pentacrinidse led the Austins 

 to establish the genus Extracrinus for a 

 fossil species which seems to have been 

 gregarious, and of which Queenstedt has 

 figured a magnificent slab, some of the 

 specimens with a stem nearly sixty feet 

 long. The stems were often twisted into 

 a solid, ropelike mass, and are so entan- 

 gled on the slab that it is difficult to 

 make out the individual stems. A sim- 

 ilar entangling also occurred among the 

 specimens dredged by the " Blake," and 

 it was often very difficult to separate speci- 



Fig. 406. — Pentacrinus 

 stage of Aetinoraetra 

 meridionalis, magni- 

 fied. 



