ECHINODERMATA. 41 



No shell. 



Body lobed or stellate STELLERIDA. 



Body elongated or vermiform HOLOTHURIOIDEA. 



Class I. CRINOIDEA. 

 PALMATOZOA. 



Mostly star-shaped animals, fixed during the whole or part of 

 life by a stalk or column. 



The body or calyx of the ventral surface is directed upwards ; 

 the stalk is on the dorsal or inferior portion. 



The greater part of the Crinoidea are extinct. Eight genera 

 are known in a recent state. 



There are three orders ; perhaps Edriaster should form another 

 order, as has been done by Huxley. It is not supposed to have 

 had any stalk. 



With arms. 



Body rounded CYSTOIDEA. 



Body cup-shaped CRINOIDEA. 



Without, arms BLASTOIDEA. 



Order I. CYSTOIDEA. 



Body rounded; enclosed in numerous pentagonal, suturally 

 united plates, and furnished with a jointed stalk; at the side "a 

 large aperture, closed by a pyramid formed of triangular plates " 

 (Huxley}. Palaeozoic. 



The use of the " pyramid " is unknown ; some suppose it to be 

 the "oro-anal" orifice. Hyponome, said to belong to this order, 

 has been recently found in Torres Straits. 



The principal genera are : 



*Caryocrinus. *Codaster. *Comarocystites. 



*Hemicosmites. *Apiocystites. *Spha3ronites. 



*Edriaster. 



Order II. CEINOIDEA. 

 BRACHIATA. 



Body cup-shaped, the dorsal portion furnished with calcareous 

 plates, the ventral coriaceous; stalked, at least when young; and 



