54 

 Family TAXOCRINID^E. 



PORBESOCRINUS WASHINGTONENSIS, n. Sp. 



Plate III, Fig. 32, azygous view of a specimen laterally com- 

 pressed; Fig. 33, view, opposite the azygous area, 

 of another specimen. 



Species medium size; plates highly convex; transverse sutures 

 nearly straight in the calyx but becoming slightly arcuate to- 

 ward the ends of the rays. Calyx constitutes two-thirds Of the 

 body. It is wider than high. The interradial areas are slightly 

 depressed so as to make the calyx obpyramidal above the 

 truncated base. The arms rapidly contract above the calyx 

 and arc infolded at the ends. Column tapers rapidly below the 

 calyx where it is composed of very short plates. 



Basals sunk within the calyx. Subradials small, three hep- 

 tagonal, two hexagonal. Primary radials four in each series, 

 three or four times as wide as high; the last one is axillary 

 and supports upon each upper sloping side three secondary 

 radials, the last one of which is axillary and supports upon 

 each upper sloping side tertiary radials. The secondary ra 

 dials are as long as the primary radials. but not quite as wide. 

 The tertiary radials \ a ry in number, in the different rays, from 

 four to nine. In the proximal series, on the left of the azy- 

 gous area, there are eight plates, in the next series four; and 

 in the proximal series, on the right of the azygous area, there 

 are six plates, and in the next series five. In the ray oppo- 

 site the azygous area the distal series have nine plates each 

 and the proximal series have six in one and seven in the 

 other. The number of tertiary plates vary, in like manner, in 

 the other two rays The last tertiary radials are axillary and 

 the proximal rays do nol divide, but each distal quaternary 

 series bears an axillary plate and supports the fifth series on 

 each of its superior sides. The number of quaternary plates 

 in the various distal series varies from nine to twelve. There 

 are. therefore, twelve arms to each ray, or sixty arms in this 

 species. 



The regular interradial areas are long and narrow, and the 

 plates vary in number in the different areas, as shown in our 

 specimens, from twelve to sixteen. The first plate rests be- 

 tween the superior sloping sides of the firsl primary radials. 



I I is succeeded by live ranges of two plates each, and above 

 these there are from one to five single plates, one above the 

 other, so that the last one extends up to the third or fourth 

 tertiary radials. The inlersecondarv areas have from five to 



