Oct., 1907. New Crixoids — Slocom. 285 



are the smallest and are not in contact with the posterior one; anus 

 unknown ; five groups of arms are situated where the interoral sutures 

 meet the radials. The distal edges of the radials are thickened- on their 

 inner side and are pierced by pores. The presence of these pores has 

 been taken by some writers to indicate that the genus might belong 

 to the cystoids, but for the present it is considered to be a crinoid. 



Zophocrinus globosus sp. nov. Plate LXXXV, Figures 15-19. 



The calyx is small, in the form of a prolate spheroid, truncated at 

 the top. The natural casts are subspherical, slightly flattened on six 

 sides, approaching a rounded hexahedron. The plates are rather thick 

 and smooth or possibly finely granulose, convex, slightly sloping towards 

 the sutures, so that their shape and arrangement is easily studied. 



Basal plates three, much thicker than the radials; two are quad- 

 rangular and about equal in size ; the other is pentangular and larger ; 

 together they form a shallow rounded cup with a slight triangulation at 

 the base and a circular depression for the reception of the column. 

 Radials four, height and width about equal ; three are pentangular, the 

 other is quadrangular; their sides are subparallel, slightly contracted 

 at either end. These plates have a decided thickening of the inner 

 margin of their distal ends, which is shown by a deep groove on the 

 natural casts. The ventral disc is not preserved on any of the spec- 

 imens studied. 



The species differs from the other species of the genus in its globose 

 form, its relatively short radial plates and its rounded base, as com- 

 pared with the pear-shaped body and attenuate obconical base of the 

 other species. These characters are stated in more detail on a later 

 page. 



Locality : Niagaran limestone of the spoil heaps along the Drainage 

 Canal, about a mile and a half east of Lemont, Illinois. 



This species, while it cannot be said to be abundant in this Area, is 

 by no means rare. Four specimens were collected by the writer in the 

 fall of 1905 and a like number in the spring of 1906. The specimens 

 consist of natural casts with more or less of the accompanying molds. 

 The Museum number of the type specimen is P 8480. 



Zophocrinus pyriformis sp. nov. Plate LXXXV, Figures 12-14. 

 The calyx is broadly pear-shaped, truncated at the top, expanding 

 rapidly from the base to about the middle of the radials, from which 

 point it contracts to the arm bases. The surface of the plates is finely 

 granulose and moderately convex, sloping towards the sutures; this 

 shallow depression indicates the position of the sutures. 



