FOSSILS OF THE BURLINGLON GROUP. 373 



thence rising moderately to the subcentral proboscis; com- 

 posed of unequal pieces, the larger of which are rather 

 tumid, and arranged in radiating rows coincident with the 

 rays and their division below, while the smaller pieces 

 between are depressed so as to form concavities between 

 the larger. 



Base narrow, truncated, but not spreading or provided 

 with a distinct rim below, wider than high, and widening 

 very gradually upward. Eirst radial pieces about of the 

 size of the basal, but proportionally longer, though they 

 are generally wider than long, two of them heptagonal and 

 three hexagonal. Second radial pieces comparatively very 

 small, and all wider than long, or transversely oblong, 

 being, as usual in this group, regularly quadrangular. 

 Third radial pieces about twice as large as the second, 

 wider than long, and all pentagonal, excepting those of the 

 two posterior rays, one of which is hexagonal and one hep- 

 tagonal, in the specimen from which the description is 

 drawn up; each supporting on each of its superior sloping 

 sides, in direct succession, two secondary radials nearly or 

 quite as large as the third primary radials themselves, 

 while each of the upper of these secondary radials is an 

 axillary piece, supporting on each of its sloping sides, in 

 direct succession, two large brachial pieces, thus making 

 four arm-openings to each ray all around, or twenty in the 

 entire series. Eirst anal piece about of the size of the 

 smaller first radials, longer than wide, and heptagonal in 

 form ; above this there are in the second range three smaller 

 hexagonal pieces, and, arching oyer the latter, four in the 

 fourth range, with a small wedge-formed piece succeeding 

 the latter above, though it is scarcely large enough to sepa- 

 rate the brachial pieces over the anal area. Eirst interra- 

 dial pieces nearly as large as the first radials, and all 

 irregularly nine-sided ; above this th ere are two smaller 

 pieces in the second range, two, or sometimes only one, in 

 the third, and above this one or two succeeding each other 



