21 



Basals stand upright, and form a cup, about one-half wider 

 than the diameter of the cokimn. having a height equal to 

 about one- third of the diameter, rather deeply notched at the 

 sutures and liaving a liemispherical depression for the at- 

 tachment of the column. Columnar canal cinquefoil. First 

 primary radials unequal in size, wider than long, three hex- 

 agonal, one heptagonal. Second jirimary radials four times as 

 wide as long, quadrangular. Third primary radials three or 

 four times as large as the second, i^entagonal, axillary, and in 

 two of the rays support on each upper side two secondary ra- 

 dials, the last being axillai-y and supporting on each upper 

 side two tertiary radials, which gives to each of these rays 

 four arms. In the other two rays, one of which is on the left 

 of an azygous area and the other between the azygous ax'eas, 

 there is on one side of the third radials two secondary radials, 

 the last being axillary and supporting two tertiary radials, and 

 on the other side a secondary radial which is axillaiy and sup- 

 poi'ts on one side two (jaateimary radials and upon the other 

 a tertiary radial which is axillary and supports two quaternary 

 radials, which ajrangement gives to each of these rays five 

 arms. There are, therefore, eighteen arms in this species. 



In each of the two regular areas there are two plates, one 

 large followed by a smaller one. In one azygous area thei-e 

 are six plates and in the other seven. The first is in line with 

 tlie tii-st prinuiry radials and of about th(^ same size. It is fol- 

 lowed, in the second range, by three plates and in the tliird 

 range by two plates in one area and three in the other. 



Vault convex and covered by tumid, polygonal plates and 

 bears a rather large subcentral i^roboscis. 



Found in the Burlington Groui3, at Burlington, Iowa, and 

 now in the collection of A. Albers, of Cincinnati. 



Remarks. —There have been described one hundred and 

 seventy-seven species of Batocrinus, from the Subcarboniferous 

 rocks of North America, and none from rocks higher or lower, 

 in the Geological .scale, if we except Aciinocrii tis praeciirsor. 

 Hall, fi'oni the Hamilton (!roup. which has been referred lo 

 Doriiviimn . by some authors, and Uiay be a Btilcn-rhnis or be- 

 long to souic otheV genus. It is certainly n(.t an ArJiiK.rrhnn's 

 and we see no reason to think it is a l)i>rijcriiiit>', Idit tlie l)a,sal 

 ami radial sci'ies ■.iro the same as in lliildcrniii^-. ( )!' lln'se oiii' 



