16 I.ARVIFORM CRINOIDS 



The upper sides of the radials, which are perhaps axillary in a few species, 

 usually hear well-developed articular processes and extend horizontally inward 

 as prominent muscle fields. The articulation consists of a strong transverse 

 ridge helow which the radial is more or less sharply beveled, and in a few 

 specimens a small ligamental pit is visible near the center of the outer side 

 of the ridge. Extending inward from the ends of the transverse ridge and 

 separated from it by shallow grooves are two strong radial ridges inclosing 

 a concave area or muscle field near the middle of which is the small opening 

 of the axial canal. The ventral surface is covered by the oral crown which 

 rises strongly above the radials. The oral plates alternate with the radials 

 and their upper flattened surfaces are broadly and shallowly concave. The 

 ambulacral openings are between the orals at a position slightly above the 

 the upper surface of the radials. The oral plates are nearly uniform in size 

 but the posterior plate may be distinguished by the fact that it adjoins both 

 the right and left anterior orals near the center of the crown, thus separating 

 the right and left posterior orals from each other. The posterior oral is a 

 madreporite and its minute perforation may be seen on well preserved in- 

 dividuals. On some specimens a tiny pustule marks the position of this pore. 

 The arms and the stem beyond its uppermost joint, which in many specimens 

 remains attached to the calyx, are unknown. 



The species Kallimorphocrinus astrus as represented by its typical va- 

 riety is selected as the genotype, several well preserved specimens of which 

 are included in our collections. This variety is an extreme representative of 

 the genus characterized by its pronounced star shape which has resulted from 

 the. development of the angulation of the radials producing wide and com- 

 paratively short articular facets. The other extreme is represented by A'. 

 pocillits with its lobate horizontal outline. The articular facets of this latter 

 species are much longer than in the genotype and the description of their 

 characters has largely been made from an examination of this species. 



The specimens of Coal Measures Kallimorphocrinus exhibit considerable 

 diversity of form and ornamentation on the basis of which they are divided 

 into ten species. 



Kallimorphocrinus astrus J. M. Weller, n. sp. 



In the collection from the Indiana locality the majority of the small 

 crinoids that belong to this genus form a rather variable series and it has not 

 been found practicable to subdivide them specifically. One of the conspicu- 

 ous end members has been selected as typical and two members of the prin- 

 cipal series are described as subordinate varieties. As may be seen from 

 figures 2a, 3a, and 4a on Plate I. the prominence of the spinelike processes 

 of the radials varies regularly as the diameter of die basal stem facet and 

 inversely as the height of the basal disc. In addition to the three described 



