448 L. Agassiz on the Echinodermata. 



C. geometricus, Goldf. — C. pinnatus, Goldf. — C. rugosus, Mill. — C. tuber- 

 culatus, Mill. — C. planus, Mill. — C.quinquangularis, Mill. — C. abbreviates, 

 Mill. — C. peutagonus, Goldf. 



22. Spii^eronites, His. {Kchinosplucrites, Wahl.) — Possessing 

 but very imperfect specimens of this genus, I am unable to give the 

 characters. It is however certain that they arc nearly allied to Cya- 

 tkocrinas. Fossils from the greywacke. 



S. pomum, His. — S. aurantium, Wahl. — S. granatum, Wahl. — S. Wahlen- 

 brrgii, Esmark. 



23. Caryocrinus, Say. — Visceral cavity surrounded by polygonal 

 laminae, forming two series of six laminae and one of eight, four of 

 which bear bifid rays. Fossils from the greywacke. 



C. ornatus, Say. — C. loricaius, Say. 



24. Cupressocrinus, Goldf. — Pedicel rounded, pierced by a canal 

 in the form of a cross ; five inflated pieces at the summit of the pe- 

 dicel between which the two first pieces of the base of the rays are 

 articulated ; they are the smallest, and on them are placed large la- 

 minae arranged in pyramids, the borders of which bear small moveable 

 appendices. Fossils from the greywacke. (C gracilis, Goldf., ought 

 in my opinion to be placed under Cyathocrinus.) 



C. crassus, Goldf. 



25. Pentremites, Say. — Body pentagonal, carried on a very short 

 pedicel surmounted by five distinct pieces, above which arise five rays 

 of a pyramidal form, which maybe compared to the interambulacral 

 spaces of an Echinus. Between the laminae of these rays we find five 

 very large interambulacral spaces situated on the upper surface of 

 the body, at the summit of which we notice five large holes alterna- 

 ting with these spaces. This genus thus presents characters ana- 

 logous to those of all the families belonging to the class Echinoder- 

 mata ; it is also one of those whose species are found in the oldest 

 deposits. 



P.jlorealis, Say. — P. ovalis, Goldf. — P. derbiensis, Sow. — P. piriformis, 

 Say. — P. ellipticus, Sow. — P. globosus, Say. 



In this synoptical table of the Radiata I have abstained from 

 enumerating all the doubtful species, trusting to be able to make 

 them better known when I publish the detailed Monograph of this 

 class, of which I have given here but a very abridged sketch. In 

 the indication of the generic characters I have endeavoured to ex- 

 press them in the most simple manner, and I have avoided all the 

 improper terms of nomenclature which Miller introduced in order to 

 describe the laminae which surround the inferior portion of the visce- 



