17 



The basals eKtend a little beyond the columu ami form a sub- 

 hexagonal band around the superior end of it, with a concave de- 

 pression radiately furrowed for its attachment. The canal is small 

 and cinque foil. The first primary radials short, about three times 

 as wide as high; three hexagonal, two heptagonal, superior side 

 slightly concave. Second primary radials small, short, (juadrangu- 

 lar, two are three times as wide as high. Third primary radials 

 very little larger than the second, pentagonal, axillary, and on the 

 distal side of the two rays adjoining the azygous area bear two 

 secondary radials, the last of which is axillary and bears two ter- 

 tiary radials on each upper sloping side, and on the proximal 

 side having a single secondary radial, which is axillary and bears 

 three tertiary radials. In each of the two lateral rays there are 

 two secondary radials on each upper sloping side of the third 

 primary radials, the second one being axillary and supporting on 

 each upper sloping side two tertiary radials. By this arrangement 

 there are four arms to each of these four rays. In the ray oppo- 

 site the azygous area the third primary radial bears upon each 

 upper sloping side three tertiary radials which gives to it two 

 arms. There are, therefore, eighteen arms to this species and 

 eighteen ambulacral openings to the vault. 



In three of the regular interradial areas one large plate is fol- 

 lowed by two small ones, in the other area there are only two 

 plates, one following the other. The azygous area is somewhat 

 triangular or conical aud contains nine plates. The first one is in 

 line with the first primary radials and somewhat smaller. It is 

 followed by three plates of nearly equal size in the second range, 

 and these by three plates in the third range, on the side of the 

 highest of which there is a small plate that might be referred to 

 a fourth range though not extending as high as the middle plate 

 in the third range, and on the apex of the middle plate there is 

 a single plate that extends as high as the calyx and unites with 

 two plates connecting with the vault. 



The vault is two or three times as large as the calyx, most con- 

 vex or tumid opi)osite the azygous side and covered with large, 

 polygonal plates, each of which bears a central node, except in 

 the azygous interradials where the plates are small and plane or 

 very slightly convex, ft bears a large subcentral proboscis. The 

 arms are arranged in pairs and two pores penetrate the vault be- 

 tween each pair of arms, which gives to this species eighteen of 

 these so-called ovarian apertures. 

 —3 



