51 



each upper side, three secondary radials, which gives to it two 

 arms. There are, therefore, seveuteen arms in this species. The 

 arm formula is 54-3+2+3+4. 



The interradial areas are unequal, but all are separated from 

 the plates of the vault. In each of two areas there are two plates, 

 one following the other. In another area there are three plates, 

 one followed by two iu the second ranj^e. In the other area there 

 are four plates, one followed by two iu the second range, and one 

 iu the third range. Tliere are eight plates in the az^gous area. 

 The first one is iu Hue with the first primary radials and some- 

 what smaller than either of them. It is followed by three plates, 

 in the second range, three in the third range, and one iu the 

 fourth range, which is cut off from the vault by the union of the 

 tertiary radials above it. 



The vault is highly convex and covered with plane, smooth, 

 polygonal plates. It bears a subcentral proboscis. No ovarian 

 pores discovered. 



This species bears little resemblance to any other seventeen 

 armed species, and, of course, nted not be compared with any 

 other; though its general appearance may be said to resemble B. 

 rolundiis, from which it is very widely separated in the essential 

 elements of structure. 



Found in the Burlington Group, at Burlington, Iowa, and now 

 iu the collection of A. Albers. 



BATOCRINDS SUBSCITULUS, U. sp. 



Plate III, Fiij. i), view opposite the azygous cirea; Fig. lo, Ixisal 

 view; Fig. 11, summit. 



Species medium si/,e, biturbinate, or Fomewhat wheel- shaped. 

 Calyx two aud a half times as wide as high, most rapidly spread- 

 ing toward the arms, which are directed horizontally, and leaving 

 tlie sides concave or a broad constriction from the basals to the 

 arms. Surface of the plates plain and smooth. 



Basals form a low expanding cup twice as wide as the diam- 

 eter of the column aud having an hemispherical depressiou for the 

 attachment of the column. First primary radials between two and 

 three times as wide as long, three hexagonal, two heptagonal. 

 Second primary radials quadrangular, three or four times as wide 

 as long. Third primary radials only a little larger than the sec- 

 ond, three hexagonal, one heptagonal aud one pentagonal, axillary, 

 and iu each of four of the rays support, on each superior sloping 



