11 



primary radials one half larger than the second, more than 

 twice as wide as long-, pentagonal, axillary, and in the ray on 

 the left of the azygous area, and in each lateral ray, bear 

 upon each superior sloping side two secondary radials, the last 

 ones of which are axillary and support on each upper side 

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

 arms. In the ray on the right of the azygous area there are 

 three secondary radials on the distal side, and two on the 

 proximal side, the last one being axillary and supporting on 

 one upper side a single tertiary radial and on the other two 

 tertiary radials, which gives to this ray three arms. In the 

 ray opposite the azygous area, the third primary radial bears 

 upon each upper side three secondary radials which gives to 

 this ray two arms. There are, therefore, seventeen arms and 

 seventeen ambulacral openings to the vault in this species. 



All of the interradial areas connect with the vault and are 

 depressed between the rays. In each regular interradial area 

 there are four plates. The first one is large, it is followed by 

 two plates, in the second range, and by one elongated plate, 

 in the third range, that unites with the plates of the vault. 

 In the azygous area there are eleven plates. The first one is 

 in line with the first primary ^radials and about as large. It 

 is followed by three plates in the second range, three in the 

 third range, two in the fourth range, and two in the fifth 

 range that unite with the plates of the vault. 



Vault conoidal and covered with small, polygonal, convex 

 plates and bearing a very small subcentral proboscis. No 

 ovarian pores have been detected. 



This is a marked species so different from all other seven- 

 teen -armed species that occur in rocks of the same age that 

 no comparison with any of them is necessary. 



Pound by N. K. Burkett in the Keokuk Group, at Keokuk, 

 Iowa, and now in the collection of Wm. F. E. Gurley. 



BATOCRINTS ST KEN QUS, U. Sp. 



Plate I, Fig. 18, azygous side; Fig. 19, side view. 

 Species small but bearing large and vigorous arms, biturbin- 

 ate. Calyx bowl-shaped, about twice as wide as high. No 

 radial ridges. Plates convex. 



