45 



BATOCRINUS REPOSITUS, n. 8p. 



Plate II, Fig. 18, azygous side; Fig. UK opposite view; Fig. •.'(),_ 



summit. 



Species medium size. Calyx obcouoidal, nearly as high as wide, 

 truncated only for a small cohimu; last radials project laterally, 

 while the interradial spaces are depressed and the ambulacral 

 openings become invisible from a basal view. No radial ridges. 

 Surface of the plates plain and smooth. Column small and round. 



Basals form a conical cup, having a height nearly equal to the 

 diameter, and it is truncated below by a small column. First 

 primary radials not as large as the basals, wider than long, three 

 hexagonal, two heptagoual. Second primary radials quadrangular, 

 from two to three times as wide as long. Third primary radials 

 a little larger than the second, one heptagonal, three hexagonal, 

 one pentagonal, axillary, and in each of the rajs, adjoining the 

 azygous area, support on each upper sloping side two secondary 

 radials, the last ones of which support, on each upper sloping 

 side a single tertiary radial, except the distal one on the left, 

 which bears an ambulacral opening on one side of the secondary 

 radial and on the other a tertiary radial. The arrangement, how- 

 ever, gives to each of these rays four arms. In one of the lateral 

 rays the third primary radial supports, upon each upper side, 

 two secondary radials, the last ones having an ambulacral opening 

 on each proximal side, and a tertiary radial on each distal side, 

 which gives to this ray four arms. In the other lateral ray the 

 structure is the same, except that one of the secondary radials 

 does not bear a tertiary plate, but it supports two ambulacral 

 openings, so that the ray has four arms. In the ray opposite the 

 azygous area, the third primary radial supports, on one side, two 

 secondary radials, the last one being axillary and supporting on 

 each side a tertiary radial, and on the other side two secondary 

 radials, the last one having a single ambulacral opening, which 

 gives to this ray three arms. There are, therefore, nineteen arms 

 in this species. The arm formula is 4+4+3+4+4. 



The interradial areas are remarkable. The first one to the 

 right of the azygous area has four plates, one in the first range, 

 and two large, elongated plates in the second range, one of which, 

 and a small plate at the side of the top of it, unite with two 

 plates belonging to the vault. The lateral area, on the same side. 



