63 



BAT0CRINU8 CONSANGUINEUS, U. sp. 

 Plate IV, Fig. 22, azygous vieiv; Fig. 23, opposite side. 



Species about medium size, somewhat biturbinate. Calyx ob- 

 conoidal, most rapidly spreading in the superior part so as to ap- 

 pear broadly constricted iu the middle part; truncated below. No 

 radial ridges. Aiubulacral openings directed nearly horizontally, 

 but not visible in a basal view, though they may be seen, in part, 

 from the summit view. Plates plane, in our specimen, though the 

 larger ones may be nodose iu other specimens. A few ovarian 

 pores only are distinguished in our specimen, but, probably 

 there is one to each ambulacral opening. The diameter of the 

 calyx is about one-half more than the height. 



Basals form a rounded cup about one-third as high as wide, 

 and very gradually spreading from the column. The columnar pit 

 is hemispherical and it is rather sharply rounded at the margin to 

 the outer side of the cup. First primary radials wider than long 

 three hexagonal, two heptagonal. Second and third radials to- 

 gether smaller than the first. First primary radials, quadrangular, 

 between two and three times as wide as long. Third primary 

 radials very little larger than the second, one hexagonal, the 

 others heptagonal, axillary, and supporting on each superior slop- 

 ing side two secondary radials, the last ones being axillary and 

 supporting on each upper side a single tertiary radial, which gives 

 to each ray four arms and four ambulacral openings to the vault. 

 There are, therefore, twenty arms to this species. The arm formula 

 is tt+4+4+4+4. 



In one of the regular interradial areas there are three plates, 

 one followed by two, in the second range. In another area there 

 are four plates, one followed by two in the second range, and one 

 in the third range. In another area there are five plates, one fol- 

 lowed by two in the second range, and two in the third range. 

 In the other area there are six plates. These areas are all cut 

 ott' from the plates of the vault by the ui ion of the tertiary ra- 

 dials, excepting the one having six plates, and one of these ex- 

 tends to the vault. In the azygous area, there are nine plates. 

 The first one is in line with the first primary radials and of about 

 the same size. It is followed by three plates in the second range, 

 three in the third range, one on the right of the top of the middle 

 plate in the third range, and one following the middle plate and 

 uniting with two plates belonging to the vault. There is one 

 plate in one of the intersecondary areas. 



