310 New Species of Crinoidea from the 



sub-radial plates and uniting with those of the adjoining 

 plates at the sutures ; these ridges form a star on each 

 sub-radial plate, the figures on the others varied according 

 to the size and shape of the plates. 



In general aspect this species is like the preceding. 

 The stelliform ridges of the body plates are strongly dis- 

 tinctive, and the angular ridges or projections on the arm 

 plates give a more directly transverse aspect to these 

 parts, and produce a more abruptly tortuous or zigzag 

 appearance than in the preceding species, while the spiral 

 aspect is not observable. 



Geological formation and locality. Burlington limestone, 

 Burlington, Iowa. 



Scaphiocrinus carinat'us (n. s.). Body small, basal plates 

 entirely covered by the column. Sub-radials three pentag- 

 onal and two hexagonal, the one on the anal side larger. 

 Radial plates three in each series : the first of moderate 

 size, sub-pentangular, a little wider than long ; the second 

 quadrangular, height nearly as great as the width ; the 

 third short, pentangular, acutely wedge-form above, sup- 

 porting the first arm plates. Arms two from each ray, 

 bifurcating on the eighth or tenth plate, and in the anterior 

 ray, and at least one of these branches from each arm 

 again bifurcating ; and a similar bifurcation is seen on one 

 of the antero-lateral rays. 



First anal plate elongate, pentagonal, resting on two of 

 the sub-radials, and supporting one of the first radials ; 

 second anal plate larger than the first, hexagonal ; the 

 third of the same form and smaller ; above these are ten 

 or twelve plates, marked by stelliform ridges, forming the 

 lower part of the proboscis. Surface of body plates 

 marked by strong radiating ridges, giving a stelliform as- 

 pect. Arms composed of a single series of plates, short, 

 and concave on the shorter side, the longer side marked 

 by a protuberance, below which it is concave ; from this 



