40 



This species bears little or no resemblance, in form or surface 

 ornamentation, to any other described eighteen-armed species. 

 The calyx has some resemblance to that of B. chrislyi, which is 

 a twenty-armed species, but, probably, looks more like B inornaius, 

 another twenty-armed species, than to any other defined species. 

 It is so widely separated from these, however, that no comparison 

 is necessary for any purpose. 



Found in the Burlington Group, at Burlington, Iowa. The 

 specific name is in honor of Mr. A. Albers, the artist, and the 

 type belongs to his collection. 



BATOCEINUS SACCELLUS, n. sp. 



Plate II, Fig. 9, azygous side; Fig. 10, opposite view; Fig. 11 



summit. 



Species medium or above medium size. Calyx urn-shaped, a 

 little wider than high. Plates convex; no radial ridges. Sutures 

 beveled. Surface granular. 



Basals form a low hexagonal cup with beveled sutures and an 

 hemispherical depression for the attachment of the column. 

 The diameter is three times the height or twice the diameter of 

 the column. The first primary radials are the largest plates in 

 the body, and are nearly as long as wide. They are about as large 

 as the second and third plates together. Three hexagonal and 

 two heptagonal. Second primary radials quadrangular and from 

 two to three times as wide as long. Third primary radials a lit- 

 tle larger than the second, each one is heptagonal and supports on 

 each of two of the upper sides, in four of the rays, two secondary 

 radials the last ones of which are axillary and support, on each 

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

 side, two tertiary radials, which give to each of these rays four 

 arms. In the ray opposite the azygous area, the third primary 

 radial bears on one upper sloping side, three secondary radials, 

 and upon the other, two secondary radials, the last being axillary 

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

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

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



The interradial areas are very ditferrent from each other; in each 

 of the two areas there are four plates, one in the first range, two 

 ill the second and one iu the third. In each of the other areas, 



