70 



CYATHOCRINUS BRITTSI, n. Sp. 



Plate IV, Fig. 35, basal vieiv; Fig. 3(1, azygous side view of the 



calyx. 



Species medium size. Calyx ratlier more thau twice as wide 

 as higli, and somewhat obpyramidal in shajje, in the superior 

 part, though round over the subradial region. Sutures dis- 

 thict, surface granular. Column large and round. 



Basals form a pentagonal disc, one-thii-d wider than the 

 diameter of the column, which has a concave depression, 

 though shallow, for the attachment of the column. Subradials 

 slightly wider than high, the one on the azygous side being 

 much larger than either of the others, though extending but 

 little higher. First radials a little wider than high, longitudi- 

 nally convex, most convex in the superior part, which gives- 

 the calyx, when seen from above, a subpentagonal outline 

 The upper part of these plates, too, is very thick^ a,nd the 

 fa3ets for the articulation of the second plates are correspond-" 

 iugly deej), and scarred very slightly, for the ambulacral canal.- 

 The facets are about three-fourths of the width of the plates,-- 

 and have a slight transverse depression that indicates a gap- 

 ing suture. The first azygous plate broadly truncates a sub- 

 i-iidial at about the middle of the first radials. 



This species will be distinguished, by its general form, fi'om 

 all others, so that no comparison with any of thorn is neces- 

 sary for its identification. 



Pound by R. A. Blair, in the Burlington Groiip, at Sodalia, ■ 

 Missouri, and now in the collection of S. A. Miller. The spe-- 

 cific naint! is in honor of Dr. J. H. Britts, one of the loading 

 naturalists- of Missouri, 



Famit,y PLATYCRINlDyE. 



PLATYCKINUS TUGURIUM, n. sp. 



Plate IV, Fig. 17 ^ basal view; Fig. 18, azygous side view; Fig. 



W, summit view. 

 This species is above medium size, and belongs rather to the 

 discoid than to the bowl-shaped forms, and receives its specific 

 name from a fanciful resemblance to a but. Calyx shallow, 

 pent-.igonal, two and a half times as wide as high. PlatyS; 

 thick, sculptured. Sutures beveled. The surface is ornamented . 



