DESCRIPTIONS OF THE SPECIES. 



295 



a glance at its base or summit (Fig. VIII.), or at the azygos interradius, is sufficient 

 to show that it is an altogether anomalous type (PL XIX. figs. 5, 6). In the first 

 place it has no trace of a stem, but the situation of the ordinary columnar facet at 

 the point of convergence of the ambulacra is occupied by the small azygos basal, x, 

 which is thus strictly dorsocentral in its position. Hall l , however, in describing a 



Fig. VIII. 



\ A; 



Diagrams to show the relations of the dorsal and radial axes in Eleutherocrinus Cassedayi 

 (adapted from Shumard aud Yandell). A, dorsal, and B, ventral aspect. 



A, B, C, D, E. The five radii of the calyx, 

 basals. d . . . d. The dorsal axis, 

 situated. 



The small azygos basal, y, z. The two larger 

 . . . r. The radial axis, in which the anus is 



new species (E. Whitfield}), speaks of it somewhat infelicitously as the " Ventral 

 basal plate." Two of the radials, A and B, rest directly against the anterior edges of 

 this azygos basal, while its rounded posterior border is in contact with two long and 

 narrow plates, the paired basals, y and z, which extend nearly halfway up the side 

 of the calyx (PI. XIX. fig. 5), and support a single spade-like radial closely resembling 

 the radial plates of some species of Codaster (PI. XIII. fig. 3). The other four 

 radials are deeply incised by narrow ambulacra of the usual character, but the two 

 which are in contact with the azygos one are naturally slightly different from their 

 fellows. Their ambulacra (C and E) are almost in a straight line (Fig. VIII. ; 

 PI. XIX. fig. 6), instead of forming an angle of twice 72° as in the regular Blastoids, 

 and the azygos ambulacrum between them is altogether different from them. It is 

 unusually wide, and entirely limited to the summit of the calyx. This is well seen in 

 Mr. Wachsmuth's specimen (PI. XIX. fig. 6), which also shows the three normal 

 deltoids, though we have not been able to make out the spiracles figured by Shumard 



1 Fifteenth Ann. Rep. New York State Cab. Nat. Hist. 1S62, p. 131. 



