ECHINODERMATA—CRINOIDEA, 5 27 



Ventral disk covered with well-defined spines. Arms four to all 

 rays, except the two posterior and five to these. 

 Lower Burlington of Missouri and Iowa. 



90. C. coelatus (Hall). (Fig. 1852.) Mississippic. 

 Large. Arms eight to each ray, slender. 



Lower Burlington of Missouri and Iowa. 



XXXV. Amphoracrinus Austin. 

 Dorsal cup flat or saucer-shaped. Calyx with five brachial lobes 

 which extend downward proximally, wholly or partly hiding the 

 cup in side view. Ventral disk highly elevated and provided with 

 an excentric, very short anal tube. Whole surface of calyx uni- 

 formly granular. Arrangement of plates mainly as in Actino- 

 crinus. Mississippic. 



91. A. divergens (Hall). (Fig. 1853.) Mississippic. 

 Dorsal cup about one third of the height of the ventral disk 



and saucer-shaped. 



Lower Burlington of Missouri, Iowa and New Mexico. 



- - \iU • ff t /f , J 



Fig. 1854. Amphoracrinus spinobrachi- Fig. 1855. Teleiocrinus umbrosus. 

 atus, X %' (After Meek and Worthen.) (After Hall, Iowa Geol., I., 2.) 



92. A. spinobrachiatus (Hall). (Fig. 1854.) Mississippic. 



Arms simple, spine-bearing. 

 Lower Burlington of Iowa and New Mexico. 



XXXVI. Teleiocrinus Wachsmuth and Springer. 

 Much like Cactocrinus. Calyx obconical to the base of the 

 palmars, then spreading horizontally and forming a broad and con- 

 tinuous rim around the calyx from the outer edge of which the 

 free arms are given off. Ventral disk short, supporting a long 



