22 



BATOOK1NTS SOLITAKH'S. 11. Sp. 



Plate II, Fig. 8, side view; Fig. 9, azygous view; Fig. 10, summit 



of same specimen, part of the ran It is gone; Fig. 11, basal 



view of same, part of the Jiang e is broken off 



of the basal plates. 



This species is above medium size, somewhat urn-shaped or 

 laterniform, and possesses remarkably large flanging basal 

 plates, such as have been made a generic character for Ereimo- 

 cinus, but more than half of the vault is preserved and there is 

 no evidence of a proboscis, or even of an azygous orifice, though 

 the plates are preserved from the azygous side straight back to a 

 small, convex, central plate, shown in figure 10. The calyx is 

 very broadly truncated at the base and expands but little and 

 very gradually above. The diameter is about one-fourth more 

 than the height. The radial series are more prominent than the 

 interradial areas, in consequence of which, the latter appear to 

 be somewhat flattened. The plates are either convex or nodose. 

 The column appears to have been comparatively small. 



The basal plates form a thin, broad, concave disc, the depth of 

 the concavity is nearly equal to their height, and, in the center of 

 the concavity, there is a concave depression for the insertion of 

 the small column. The tirst primary radials are unequal in size, 

 from two to three times as wide as high, each hears a tranverse, 

 cuneiform node, three hexagonal, two heptagonal. Second pri- 

 mary radial i about three times as wide as high, quadrangular. 

 Third primary radials one-half larger than the second, nodose, 

 pentagonal, axillary, and support on each upper sloping side two 

 secondary radials, the last ones of which are axillary and sup- 

 port on each upper Sloping side two tertiary radials. This is 

 the structure of two rays and of one-half of each of two other 

 rays, one of which is opposite the azygous area, we believe, 

 therefore, that all of the rays are substantially alike and that the 

 species bears twenty arms and twenty ambulacra! openings to 

 the vault. 



None of the interradial areas connect with the vault. In the 

 r 'ular interradial areas there are three plates, one large nodose 

 plate followed by two small ones. In the azygous area there 

 an' seven plates, the first one is in line with the tirst primary ra- 

 dials and nearly as large, it is followed by three plates, in the 

 second range, and three plates in the third range, which are cut 

 off from the vault by the union of the tertiary radials above them 



