314 Mr. Say on Crinoidea. 



In a natural series these bodies constitute the link between the 

 Crinoidea and the Echinidea, on the one hand, whilst on the 

 other, the former is unquestionably, but not more obviously con- 

 nected with the Stelleridica, by the unequivocal intervention of 

 Comatula and Marsupites. Of all the genera of Crinoidea, it is 

 to Platycrinites that Pentremite seems most closely related. 



Species, 



1. P. globosa. Body subglobular; sutures with parallel im- 

 pressed lines. Length one inch and one-fifth ; greatest breadth 

 one inch and three tenths. 



Description. — Pelvis deep saucer-shaped, convex; longitudinal 

 sutures without parallel lines of increment, but these are very 

 obvious at the terminal margin : scapulars with the impressed 

 lines of increment very obvious at base ; and near the tip each 

 side : ambulacrae with impressed lines equidistant between the 

 central line and the lateral series of pores. 



This large and fine species belongs to the Philadelphia Museum. 

 It was brought from England by Mr. Reubens Peal, who under- 

 stood that it was found in the vicinity of Bath. None of this 

 species, I believe ; has yet been found in America. The parallel 

 Ihies of increment margining the sutures, distinguish this from 

 the following species. 



2. P. pyriformis. Body oblong, pelvis gradually attenuated. 

 Length from three-quarters to one inch and a quarter. 



This species is found in plenty in Kentucky, in the same locali- 

 ties, and intimately intermixed with the succeeding species ; it 

 may be readily distinguished by the gradual attenuation of the 

 pelvis and contiguous parts, from the tips of the emarginations of 

 the scapulae, to the origin of the column. The first specimen I 

 saw, was dug up in a garden at Reading, and was sent to my 

 brother, B. Say, under the name of " petrified althea bud." 



3. P.Jlorealis^ Schloth. Pelvis terminating abruptly, nearly 

 horizontal. 



Length from seven-tenths to nearly half an inch. 



