42 



PLATYCRINUS BOZEMANENSIS, n. Bp. 



Plate III, Fig. 5. view showing the arms and calyx except a small 

 piece which is broken off. 



Species medium size and belonging to the round, bowl-shaped or 

 goblet-shaped forms. Calyx round, bowl-shaped, constricted above 

 the base so as to leave a flange below, and about as high as wide. 

 Sutures distinct, surface smooth or granular. Column flattened, 

 twisted, and composed of thick plates. 



The basals form a cup. constricted above the base. First radials 

 longer than wide, with a very slight increase in width upward. Ar- 

 ticulating facets for the second radials occupy one half the width of 

 the plates. Second radials very short, axillary, and bear upon each 

 upper sloping side two secondary radials, the last being axillary and 

 bearing, upon one side, a free arm, while the other arm bifurcates, on 

 the second plate, which arrangement gives to each ray six arms. 

 There are, therefore, thirty arms in this species. The arms are robust 

 and in the lower part are composed of cuneiform plates, but above, 

 they are composed of a double series of interlocking plates. They 

 bear long, coarse pinnules. Vault unknown. 



If we had only the calyx of this species we might be unable to dis- 

 tinguish it from some of the smooth, round, constricted forms, but 

 the coarse thirty arms will serve, at all times, to distinguish it. An- 

 other specimen than the one illustrated shows the constricted basal 

 plates. 



Found by Earl Douglass, on Bridger Mountains, near Bozeman, 

 Montana, and now in the collection of S. A. Miller. 



PLATYCRINUS SHARONENS1S, U. Sp. 



Plate III, Fig. 6, basal view; Fig. 7, side view of basal plates. 



We have a number of large basal discs of Platycrinus, which are 

 too poor for proper specific definition, though we know they are un- 

 described. We usually think we know the column of a Platycrinus, 

 by its twisted form and elliptical, transverse section, but we fre- 

 quently find them larger than any described species. We have, in 

 this instance only the basal plates, but they are so striking and ex- 

 traordinary that we feel warranted, though with some hesitation, in 

 giving them a name. 



