25 



BATOCRIXrS BKSERVATUS, n. sp. 



Plate 1. Fig. 22, based vicir mafjuijieil fico diameters; Fig. 23, same 

 iiatimd size; Fig. 21, nzi/goiis side: Fig. 25, summit view. 



Species below medium size, hiturliiimte. wheel-sliaped. Calyx 

 very rapidly spreading at tlic arms, where it is twice as wide as high. 

 No radial ridges, lint the radial series are lobed and project at the 

 inargln so as to notch the circumference at the interradial spaces. 

 Plates plane and smooth, or finely granular. Ambulacral openings 

 directed upward and not visible in a l)asal view, but fully exposed in 

 a summit view. An ovarian pore may be seen on each side of each 

 radial series, the opening is through the last radial and is small so as 

 not to be very distinct. 



Basals form a short, rounil. ex]iaiiding cu]i. twice as wide as high, 

 and having an hemisj)herical depression for the attachment of the 

 column. First ])rimary radials as large as the second and third to- 

 gether, wider than long, three hexagonal, two heptagonal. Second 

 primary radials, ((uadrangular, about twice as wide as long. Third 

 primary radials a little larger than the second, three hexagonal, two 

 l)entagonal. axillary, and. in the ray opposite the azy,gous area, sup- 

 |)orts, on each upper sloping side, three s("condary radials, which 

 gives to this ray two arms. In imc of the lateral rays, the third 

 jirimary radial su|)i)orts, on each upper side, two secondary radials, 

 the last ones axillary and snijporting, on the distal sides, two tertiary 

 radials. and, on the proximal sides, one. which gives to this ray four 

 arms. In the other lateral ray. there are three secondary radials on 

 one side, and two on the other, the last one being axillary and sup- 

 porting, on each side, two tertiary radials, which gives to this ray 

 three arms. In the ray. on each side of the azygous area, the third 

 l)rimary radial bears, upon each distal side, three secondary radials, 

 and, upon each proximal side, two secondary radials, the last being 

 axillary and supporting on each upper side, two tertiary radials, 

 which gives to each of tlu'se rays three arms. There are, therefore, 

 fifteen arms in this species. The arm formula is .5 | 4+2+3-f-8- 



In each regular interradial area there are three plates — one in the 

 first range, followed by two elongated plates in the second range 

 that unite with the plates of the vault. In the azygous area there 

 are four plates. The first one is in lijie with the first primary radials 



