9 



than wide, three hexagonal, two heptagonal and rising almost 

 vertically from the basals. Second radials quadrangular, about 

 half as wide as the first, but nearly twice as wide as long. 

 Third radials a little larger than the second, three hexagonal, 

 two pentagonal, axillary and bear upon each superior sloping 

 side the secondary radials. In the ray opposite the azygous 

 side and in one of the lateral rays there are two secondary 

 radials, in each series, the last one much longer than the first, 

 which gives to each of these rays two arms. In each ray ad- 

 joining the azygous area there are two secondary radials on 

 the distal side and one on the proximal side which is axillary 

 and bears upon each upper sloping side a single tertiary 

 radial. One of the lateral rays is constructed in the same 

 way. Each of these three rays bears three arms. It is also 

 to be observed that the radials which support the arms are 

 longer than those immediately below. There are, therefore, in 

 this species thirteen arms. 



In one of the regular interradial areas there are three plates, 

 one followed by two in the second range. In the other areas 

 there are only two plates, one following the other. These 

 areas do not connect with the vault. In the azygous area 

 there are seven plates. The first one is in line with the first 

 primary radials and is the largest plate in the body. It is 

 followed by three plates in the second range and three in the 

 third range. The middle plate in the third range is elongated, 

 separates the tertiary radials and unites with two plates be- 

 longing to the vault. 



Vault elevated, convex, and bears a submarginal proboscis. 

 It is covered with large, polygonal, smooth plates. 



This is the first species of Batocrinus bearing only thirteen 

 arms that has ever been described, from the Burlington Group, 

 and its arm formula, therefore, is sufficient to distinguish it 

 from all other species. In form, it approaches more nearly 

 B. christyi, which has twenty arms, than any other species. 



Found by Mr. C. S. Hodgson, a naturalist of Albion, Illinois, 

 in whose honor I have proposed the specific name, in the 

 Burlington Group, in Adams County, Illinois, and now in the 

 collection of S. A. Miller. 



BATOCRINUS ARGUTUS, n. Sp. 



Plate I, Fig. 8, azygous side; Fig. 9, opposite view. 



Body medium size, calyx and vault, subequal in size, making 

 it biturbinate. Calyx rather broadly truncated below, and most 

 —2 



