PALEONTOLOGY OF IOWA. 687 



Agassizocrinus constrictus ( n. s.). 



PLATE XXV. FIG. 10. 



BODY elongate-turbinate : base long and narrow, constricted 

 at the junction of the subradial plates, and swelling above. 

 Basal plates extremely elongate, narrow; a small intercalated 

 plate at the base, on the anterior side : subradials contracted 

 at the base and gradually spreading above, more than once 

 and a half as long as wide, hexagonal. First radials small, 

 wider than long. Second radials and arms unknown. 



This species differs so conspicuously from any other known species of the genus, 

 that it can be readily identified. 



Fig. 10. The anterior side of the specimen, natural size. 



Fio. 115. 



The diagram illustrates the form of the basal, subradial and 

 radial plates. The small intercalated plate at the base is pro- 

 bably accidental. 



Agassizocrinus conicus : OWEN A SHUMARD, Geological Report of Wisconsin, Iowa and 

 Minnesota, pa. 597, pi. 5, f. 6. 



Geological position and locality. In the Kaskaskia limestone : Chester, 

 Illinois. 



The solid turbinate basal pieces of this species are very common in the Kaskaskia 

 limestone at Chester and elsewhere, and are readily distinguished from either of the 

 species described above. 



Cyathocriiius ? pentalobus ( n. s.). 



PLATE XXV. FIG. 5 a, b. 



BODY depressed, broadly and deeply concave at the base, 

 the concavity extending to the middle of the subradial plates : 

 outline pentagonal, with the angles extremely produced. 

 Basal plates minute, hidden by the column, which fills the 

 exterior cavity of the base : subradial plates large, hexago- 

 nal (except on the anal side), about half the length of the 

 plate curving downwards into the basal cavity, the upper 

 part projected laterally into prominent obtusely angular 



