54 SIB C. WTVILLE THOMSON ON NEW LIVING CRTNOIDS. 



size fringe the radial grooves and the grooves of the arms and 

 pinnules. The ovaries are very long and narrow, extending three 

 fourths of the length of the first three or four pinnules on each 



arm. 



Fiu'. 5. 



Arrangement of the soft parts in Hyocrinus bcthellianiis. a, oral valves ; 

 b, oral vascular ring ; c, oral tentacles ; d, e, inner aspect of the oesophagus and 

 stomach ; /, intestine; g, loose areolated connective tissue. Eight times the 

 natural size. 



The assemblage of characters connected with the disk and soft 

 parts thus shows a considerable resemblance between Hyocrinus 

 and EJiizocrimis. My strong impression is that the mode of nu- 

 trition of the Cj^athocrinidas, and consequently the structure and 

 arrangement of their disk, was essentially different from that of 

 all the yet known living forms ; and I think it probable that when . 

 we have an opportunity of studying the structure of Hyocrinus 

 carefully, we shall find that its striking resemblance to Platycri- 

 nus is in a great degree superficial. 



The following are, I believe, all the Crinoids, referable to the 

 Apiocrinidse, which we have hitherto met with during our deep- 

 sea explorations : — 



Hhizocrinus lofotensis, Sars. 

 ^athycrinus aldricliianus, sp. n. 

 B. gracilis, sp. n. 



