272 Neio Species of Crinoidea from the 



First intcrradial plate hexagonal, as large as the second 

 radials or larger, supporting two smaller heptagonal plates 

 in the second range, with three in the third, and three or 

 four in the fourth ; and above these are still smaller plates, 

 which unite with the plates of the dome. First anal plate 

 heptagonal, as large as the first radial plates, supporting 

 three smaller plates in the second range, with four in the 

 third range, above which are ten to fifteen smaller, irregu- 

 lar plates. 



Arms two from each ray, bifurcating soon after becom- 

 ing free ; the branches, strongly diverging and curving up- 

 wards, again bifurcate, and still strongly divergent. The 

 arm plates are a single series of obtusely wedge-form plates 

 near the base, becoming double from the fourth or fifth 

 plate, after which they continue in double series. At eacji 

 bifurcation the arms gradually diminish in size. 



Surface smooth, with an incipient ridge passing along 

 the middle of the radial series. Column round, of moder- 

 ate strength, composed of very short plates. 



This is a very distinct and well-marked form, though the 

 bifurcations of the arms vary in different individuals. 



Geological formation and locality. Burlington lime- 

 stone, Burlington, Iowa. Collections of C. A. White and 

 Dr. Thieme of Burlington, 



Actinocrinus fiscellus (n. s.). Body discoid, flattened or 

 slightly concave, to the extent of the third radial plates, 

 from which it rises abruptly with little increase in width 

 to the arm bases ; strongly pentagonal, the anal side much 

 the largest. Basal plates small, extending little beyond 

 the column. First radial plates proportionally large. 

 Second radial plates quadrangular, wider than high. 

 Third radial plates short and wide, pentangular, obtusely 

 wedge-form above, supporting on each upper side, in the 

 anterior and antero-lateral rays, a series of brachial plates, 

 giving two arms to each ; in the postero-lateral rays they 



