NEOCRIXOIDEA. 



439 



radial ridges, and each exhibits in the centre a small round or 

 pentagonal neurovascular canal (see the lower figure in fig. 312). 

 Lastly, the visceral mass was enclosed in a plated perisome essen- 

 tially similar to that of the recent Crinoids. 



The only clearly established genus belonging to this family is 

 Encrinus itself, all the species of which are Triassic. A well-known 

 species of this genus is the Lily-encrinite (E. liliiformis, fig. 312), 

 the heads of which are not very rare in some localities in the 

 Muschelkalk of Germany. 



Family 2. Eugeniacrinidce. — In this singular family, the calyx 

 (fig. 313) is apparently composed only of primary radial plates, 

 which rest directly upon the enlarged uppermost joint of the column. 

 Basals have not been detected, but it is prob- 

 able that they were present in a rudimentary 

 form. There are two additional rows of radials, 

 which bear ten uniserial arms, and the base of 

 the column is expanded, and serves to cement 

 the animal to foreign bodies. The geological 

 range of the family is restricted to the Jurassic 

 and Cretaceous rocks. 



The principal genus of this family is Eugenia- 

 crinus itself (fig. 313), which occurs in the 

 Jurassic and Cretaceous deposits of Europe. 

 The column-joints and clove-shaped calyx of 

 species of this genus are not uncommon, but 

 the arms have never been found attached to the 

 cup, and no example of a complete calyx has 

 yet been detected. 



Family 3. Holopidce. — In this aberrant fam- 

 ily the calyx is without a column, and is 

 firmly adherent to foreign bodies by the un- 

 der surface of the wide cup. The basals are ^Sas! 

 fused with one another, and usually with the 

 radials also, in which latter case the presence of distinct basals can 

 only be inferred. The arms (where known) are thick, massive, and 

 spirally inrolled. 



In the recent genus Holopus the basals and radials are " com- 

 pletely anchylosed into an asymmetrical tube-like calyx, which is 

 fixed by an irregularly expanded base " (P. H. Carpenter). Allied 

 to this extraordinary living type are a few fossil forms from the 

 Mesozoic and later Tertiary deposits. Of these the genera Cotyle- 

 crinus (Cotyledermd) and Eudesicrinus are confined to the Lias; 

 while Cyathidium is found in the late Cretaceous deposits (Faxoe 

 Limestone) and in the Eocene Tertiary. 



Family 4. Hyocrinidce. — This family includes only the living 



— Engeniacri- 

 nus caryofihyllatiis, with- 

 out the arms, restored. 

 Jurassic rocks. (After 

 copied from Zittel.) 



