11 



an orifice at each of its inferior angles. This arrangement places 

 one pore on one side of each arm or gives to the species twenty 

 of these so-called ovarian pores. 



This species is distiuguished by its general form, cuneiform 

 basal plates, elongated interradial areas, twenty arms and nodose 

 plates. It cannot be mistaken for any hitherto described. 



Found by Prof. A. G. Wetherby, in the Keokuk Group of Ten- 

 nessee and now in the collection of VVm. F. E. Gurley. 



lUTOCRINUS WETHERBYI. 



PUde I, Fig. 11, az>j(]ous view; Fig. 12, opposite side of same 

 specimen. The oider rim of the hasals is broken off. 



Species rather above medium size, biturbinate vault larger than 

 the calyx. Plates of the vault tumid and nodose, while those of 

 the calyx are smooth. Calyx twice as wide as high, truncated 

 and expanded at the base, and broadly constricted in the region 

 of the secondary radials, and having the last tertiary radials 

 directed nearly horizontHlly. The surface is without radial ridges 

 or other ornamentation except a granular covering. 



TLe basals are truncated below and broadly expanded, but the 

 outer rim is broken off in our specimen "so the true diameter is 

 not disclosed. The column is large aud inserted in a concave rad- 

 iately furrowed depression. Tbe first primary radials are very 

 short, from three to four limes as wide as long, i-uperior face 

 concave, three hexagon-il and two heptagonal. Second primary rad- 

 ials short, from two to three times as wide as \<>nj:, quadrangular. 

 Third primary radials very little larger thin the second, pentag- 

 onal, axillary and supports on each superior sloping side two 

 secondai-y radials. The secondary radials are larger than tlie sec- 

 ond and third primary radials and considerably wider. The second 

 secondary radials are axillary and bear on each superior sloping 

 side two rather long tertiary radials. By this arrangement there 

 are twenty arms and tweutj' ambulacral openings to the vault. 



There is a single very large plate in each of two regular inter- 

 radial areas and two plates in each of the other two areas, one 

 rather large plate followed by a small one as shown in figera 12. 

 There are five azygous plates. The first one is much larger than 

 either of the first primary radials and in line with them. There 

 are three plates in the second range, the middle one being much 

 the smallest and quadrangular. There is a single wide plate in 

 the third range which is nearly as large as the first. The azygous 

 area is, therefore, nearly square iu outline, with a small quad- 

 rangular plate in the center surrounded by four plates in the angles 

 of the area. 



