8 



DOLATOCRINUS SPINOSUS n. sp. 



Plate I, Fig. 4, basal view of the calyx, without the surface mark- 

 iiigs of the plates; Fig. 5, lateral view, showing some 

 of the spines on the plates of the vault. 



Calyx large, subhemispheroidal, broadly lobed in the radial fields, 

 and depressed concave od the lower side. Apparently no azygous 

 interradius. The diameter of the specimen illustrated is two and 

 two-tenths inches, and height three-fourths of an inch, though we 

 have seen specimens only about two-thirds as large. Yault moderately 

 convex and slightly depressed in the interradial areas. A strong 

 ridge crosses the primary radials. Column round and deeply in- 

 serted in the calyx. Surface ornamentation not preserved in any 

 of our specimens. 



Basal plates sunk deep within the calyx and extending internally 

 as high as the arm openings. First primary radials twice as wide 

 as high externally, but near the middle of the plates they are 

 abruptly bent, almost at right angles, into the basal cavity, where 

 they form a funnel to the basal plates, into which the column is 

 inserted, so that, in fact, their length is fully equal to their great- 

 est width. The superior face is slightly concave. 



Second primary radials quadrangular and more than one-half 

 wider than high. Third primary radials slightly larger than the 

 second, pentagonal, a little wider than high, and supporting upon 

 each upper sloping side a single secondary radial. 



Secondary radials nearly as large as the third primary radials 

 pentagonal, and supporting upon each upper sloping side a series 

 of three tertiary radials, the last one of which bears the free arms. 

 The first tertiary radials are larger than the second or third. The 

 species bears twenty arms. 



The first inter radials, in each area, are elongated eleven sided 

 plates and larger than any of the other plates in the body. Each 

 one is followed by an hexagonal plate that is as long or longer than 

 wide and supports three narrow, elongated plates in the third 

 range that reach as high as the base of the arms. These are fol- 

 lowed, in the fourth range, by three plates that separate the arms, 

 and unite with the plates of the vault. One or two intersecond- 

 ary plates (apparently a pair of them) are inserted at the base of 

 the arms in the intersecondary areas, but it is not clear, in our 



