ECHINODERMA TA—BLA ST OWE A . 48 5 



21. S. melonoides (Meek and Worthen). (Fig. 1798.) 



Mississippic. 

 Cross section somewhat lo-sided owing to broad vertical inter- 

 radial ridges. 



Burlington of Missouri and Iowa. 



22. S. sayi (Shumard). Mississippic. 

 Distinguished from S. melonoides by the large size of its del- 

 toids which form almost the whole of the calyx. (Type of genus.) 



Burlington of Missouri and Iowa. 



Fig. 1798. Schizoblastus melonoides^ two views of a specimen, X 2. 

 (After Etheridge and Carpenter.) 



IX. Cryptoblastus Etheridge and Carpenter, 

 Calyx subglobose, lobate, with a flattened or slightly concave 

 base. Basals small. Radials long and deeply incised, making up 

 more than three quarters of the calyx. Deltoids small, triangular. 

 Spiracles two in each of the four anterior plates but merged with 

 the anus in the posterior. Lancet plate separated from the radials 

 by a hydrospire plate but coming into direct contact with the del- 

 toids. Mississippic. 



23. C. melo (Owen and Shumard). (Fig. 1799, 6.) Mississippic. 



Summit wider than base. Ambulacra nearly linear. Surface 

 granular. (Type of genus.) 



Burlington of Illinois, Missouri and Iowa. 



X. Granatocrinus Troost. 

 Like Sch'izohlashis in general appearance. Calyx ovate to glo- 

 bose, with slightly concave to deeply funnel-shaped base. Section 

 pentagonal, round, or roughly decagonal. Interradial areas more 

 or less depressed. Basals small, usually concealed in the central 

 cavity of the stem. Radials very variable in size, often long and 

 invariably turned in below to assist in forming the base. Deltoids 



