Found by E. A. Blair, in tlio Biirliiijitoii (Iroup, near Sliaroii. in 

 tlu' sonfliwcst |)arf of Missouri, and now in flic collcotion of S. A. 



Mill.T. 



HATOCItlNTS SENI':\. II. S]). 



I'ldlc I, Fiij. I'.. <i'-!l'.l<>ii^ >:itlf: h'iij. i:/, opiinsilc ricir of .•^niic sjicci- 

 iiicii: Fif/. II. sininiiil ricir of idiollicr kjh'ciikcii. 



8])ocies below ineiliiiin size, biturliiuate. Caly.x ohconoidal. most 

 rapidly spreading' at the arms, more than one and a half times as 

 wide as hiifh. No radial ridges, but liepressed at the ni)per part of the 

 interradial areas K'avinij; the radial series projeetinLC at the basi's of 

 the arms. Plates smooth, the laryer ones slitjhtly convex. Aiubu- 

 hicral openings not visible in a basal view, but conspicuous in a sum- 

 mit view. An ovarian pore on each sidi' of the radial series oppo- 

 site the azj'gous area, others iifit discovered. 



Basals form a low exiianding cup nearly four times as wi le as 

 high and having an liemis])herical depression below, for the attach- 

 ment of the column, which has a diameter ei(ual to the truncated 

 end of the calyx. No basal rim. First primary radials large, nearly 

 as long as wide, three hexagonal, two heptagonal. Second j^riniary 

 radials riuadrangular. two or three times as wide as long, and less 

 than half as large as the tirst. Third ])i-imary radials about half as 

 large as the first, the two adjoining the azygous area hexagonal, the 

 other three pentagonal, and in the ray oppositi' the azygous area 

 supports oii each upper sloping side two secondary radials. which 

 gives to this ray two arms. In each of the lateral I'ays the thii-d 

 primary radial bears u))on one upper sloping side three seccjndary ra- 

 dials and upon the other two secondary radials. the last being axil- 

 lary and sujjporting. on cacli U2)|)er slo])ing side, a single tertiary 

 radial, which gives to each of these rays three arms, Tn the ray on 

 each side of the azygous area, the third primary ratlial bears u[)on 

 the distal side three secondary radials and u]>on the proximal side 

 two secondary radials. the last being a.\illary and bearing, upiin cmc 

 upper side, a single tertiary radial, and upon the otluT two terliary 

 radials, which gives to each of thesis rays three arms. Thi're are, 

 therefore, fourteen arms in this species. The arm formula is 3 [-3 | 

 2+8 f 3. 



In each of three regular interradial areas, there are three plates, 

 one in the first range and two elongated plates in the second range, 

 one of which connects with a plate belonging to the vault. In the 



