J24 



[Senate 



The accompanying figure is of this species. 

 1 



PiG.l, is in a position with tlie body erect, as we usually view crinoids; but the direction of 

 the column shows this to be unnatural. 



"Bid. 2) is in a position the body would take with the column in its natural direction. 



The animal doubtless had the power of erecting its body ; and by elevating itself so 

 that the edges of the basal and lower dorsal plates would meet, the basal plate would 

 be nearly in line with the plates above, and the body nearly erect. 



CIIEIROCRINUS TUNICATUS(n.s.). 

 Body strong, the dorsal side flattened, narrowing above, the cavity shallow. Basal 

 plate wide and short; first dorsal plate triangular; dorso-lateral plates wide, 

 five-sided, supporting a small upper dorsal plate above : ventral arch of two 

 narrow pieces. The plates of the dorsal side, and those of the ventral arch, are 

 all anchylosed together as shown in the diagram. 



CheIROCRINXTS TUNICATUS. 



1. Basal plate, showing the point of attachment for column. The figures 

 indicate the plates, as given in the preceding diagram : c, the 

 cicatrix, for a strong tendon which connects the dorsal with the 

 basal plate ; a shows the direction of the dorsal arm ; a' a', faces 

 of attachment for the lateral arms. 



From the Keokuk limestone. 



CHEIROCRINUS NODOSUS (n.s.). 

 Body robust; form of plates similar to the preceding, with the basal plate longer, 

 and the upper sides of the do**so4ateral plates and the upper dorsal plate nodose. 

 Dorsal arm strongly nodose between the joints : lateral arms consisting of a 

 series of simple nodose plates, extended laterally from the brachial plate; and 

 from the upper faces of these the lateral arms extend longitudinally or parallel 

 to the dorsal arm, some of them bifurcating above, and strongly nodose at the 

 junction of every third plate. Fro the Keokuk limestone. 



I have been indebted to the Collections of Messrs. E. Jewett, A. H. Worthen", 

 B. J. Hall and C. A. WaiTE, and of the Crawfordsville College through Mr. E. 0. 

 HovEr. Full descriptions and figures will be given in a future Report. 



