284 New Species of Crinoidea from the 



lower part of the first radial plates is slightly depressed, 

 and destitute of ornament, except the finely granulose tex- 

 ture which marks the whole surface. 



These surface characters distinguish this species from 

 every other of the geims. 



Geological formation and locality. Burlington lime- 

 stone, Burlington, Iowa. Collection of C. A. White. 



Agaricocrinus { Amphorae rinus) injlatus (n. s.). Body de- 

 pressed-convex, strongly inflated on the anal side ; inteiTa- 

 dial spaces somewhat depressed on the outer side ; dome 

 elevated, terminated by a large polygonal plate, which in 

 some specimens is strongly tuberculous and in others sub- 

 spiniform. Basal plates of moderate size, excavated about 

 two thirds for the attachment of the column. First radial 

 plates hexagonal. Second radial plates broad, quadrangu- 

 lar. Third radial plates short and broad, pentangular, 

 succeeded on each upper side by a series of short, broad, 

 plates, which support the first arm plates. 



First interradial plates eight-sided, sub-circular or sub- 

 ovate, reaching nearly to the edge of the dome, succeeded 

 by two small, somewhat elongate plates in the second 

 range. First anal plate seven-sided, succeeded by three 

 smaller plates in the second range, with numerous medium- 

 sized plates above. Anal opening near the base of the 

 large central node or sub-spine. Dome plates unequal, 

 the larger ones slightly tuberculose. Arms broad at base, 

 and from the back to the inner face less thick than in most 

 species of this genus. Surface of body plates smooth in 

 the young, becoming more convex in older specimens. 



Tills species may be distinguished from A. pentag-onis 

 var. convexus {1st Supp. Iowa Geol. Rep. page 58) by the 

 basal plates extending some distance beyond the circum- 

 ference of the column, and the dili'erent proportions of the 

 radial plates; also the interradial spaces are not contracted 

 in that species. The peculiarity of this species consists in 



