282 



CRINOIDEA. 



centric and not prolonged into a proboscis ; and there is a 

 peculiar internal skeleton (as in various Palseocrinoids) for 

 the support of the viscera. The column is 

 obtusely quadrangular, annulated, and tra- 

 versed by a large central canal surrounded 

 by four smaller tubes. The Carboniferous 

 and Devonian Symbatlwcrinus, and the 

 Devonian Phimocrinus are nearly related 

 to Cupressocrinus. 



In the family of the Encrinidce, we have 

 Crinoidswith freely-articulated radial plates 

 (Crinoidea articulata). The calyx consists 

 of five basals, five parabasals, and three 

 cycles of radials (fig. 168), but there are 

 no inter-radials. The arms are composed 

 of a double series of alternating pieces, 

 and carry pinnules on their inner faces. 

 The column is long, composed of round 

 joints, with articulating surfaces grooved 

 in a radiating manner, and pierced by 

 a small round central canal. The chief 

 genus is Encrimis itself, well known by 

 the beautiful E. liliiformis (fig. 168) of 

 the Muschelkalk. All the genera of the 

 family are Triassic. 



In the Eugeniacrinidce are imperfectly 

 known and comparatively small Crinoids, 

 principally from the Jurassic, but extend- 

 ing upwards into the Cretaceous. In 

 Eugeniacrinus the calyx consists of five 

 basals, and three cycles of radials ; but 

 there are no parabasals or inter-radials. 



In the Pentacrinidce, typified by the 

 well-known, genus Pentacrinus (fig. 157), 

 the calyx is small, composed of five basals 

 and three cycles of radials, without either 

 parabasals or inter-radials ; the arms are 

 long, abundantly and irregularly ramified ; 

 and the column is pentagonal, the articulating surfaces being- 



Fig. 169. Apiocrinus 

 Roissyarms. Middle Oo- 

 lite (Jurassic). 



