23 



of these rays six arms. In the ray opposite the azygous area, the 

 third primary radial bears, upon one side, four secondary radials, 

 and upon the other, two, the last being axillary, and supporting, 

 upon each upper sloping side, two tertiary radials, which gives to 

 this ray three arms. There are, therefore, twenty- three arms in 

 this species. The arm formula is 6+4+3+4+6. 



In each regular interradial area there is a large tumid plate, 

 and, in two of the areas, it is followed by a very small plate. 

 The azygous area contains only four plates. The first one is in 

 line with the first primary radials and quite as large as either of 

 them. It is followed by three plates, the middle one being the 

 largest, and cut off from the plates of the vault by the union of 

 the quaternary radials above it. 



The vault is highly convex and covered with numerous polyg- 

 onal, nodose plates. It bears a subcentral proboscis. 



This species differs, in general outline, and in the surface of 

 the plates, from B. subaequalis of McChesney, which has three 

 regular interradials in each area and seven or eight irregularly 

 arranged plates, in the azygous area, beside the arm formula, in 

 that species, is 6+4+4+4+5. The two species have so little re- 

 semblance to each other, though they have the same number of 

 arms, that no further comparison is necessary. This species has 

 even less resemblance to B. pistillus of Meek & Worthen, which 

 has four regular interradials and seven or eight azygous plates 

 and the arm formula of 5+4+4+5+5. These are the only twenty- 

 three armed species, that have been described from the Burling- 

 ton group, and our species cannot be mistaken for any other. 



Found in the Burlington Group, of Adams county, Illinois, and 

 now in the collection of Charles L. Faber. 



BATOCRINUS LEVIS, n. sp. 



Plate I, Fig. 13, basal view; Fig. 14, azygous side; Fig. 15, 



summit view. 



Species medium or below medium size, calyx somewhat obco- 

 noidal, rounded below, broadly constricted in the middle and more 

 or less quinquelobate when seen from above, caused by the de- 

 pression, at the interradial areas. There is considerable variation 

 of the forms in different specimens. Surface of the plates, plane 

 and smooth, those of the vault sometimes slightly convex. 



