NATURAL SCIENCES OF PHILADELPHIA. 385 



with a subcentral proboscis ; interradial spaces between the arms deeply exca- 

 vated. Base rather small, truncated and concave below, about four times as 

 wide a3 high, not provided with a continuous rim; composed of somewhat un- 

 equal plates, with deeply grooved sutures between ; columnar facet nearly two- 

 thirds as broad as the base, concave, and marked by fine radiating striae. First 

 radial plates a little wider than high, two of them hexagonal, and three hepta- 

 gonal, the angle at the middle of the lower side of each being very obtuse. Sec- 

 ond radials wider than long, hexagonal and heptagonal, about one-half to two- 

 thirds as large as the first radials, and like them ranging obliquely outward 

 and upward from the base. Third radial pieces, smaller than the second, from 

 which they extend almost horizontally outwards ; arcuate transversely, their 

 lateral extremities curving up to connect with the superior arm pieces, hexa- 

 gonal, and each supporting on its superior (_or more properly its outer) sloping 

 sides two secondary radial pieces, which also extend out horizontally from the 

 body. 



The first anal piece is nearly as large as the first radials, about as wide as 

 long, hexagonal, and supports on its superior sloping sides two smaller hexa- 

 gonal and heptagonal pieces in the second range ; above these there are in the 

 next range, three or four smaller pieces, which connect with the vault and 

 superior arm pieces above and on each side. The first interradial plates are 

 about the size of the second radials, as long as wide, heptagonal (and hexago- 

 nal) and support two or three smaller pieces in the next range. 



Of the distinct radiating costse on the first radial plates, from three to four 

 pass across from one to the other, and from each to the base, and one or two 

 to the second radial, and each first interradial above ; while the third radials 

 are destitute of costae. 



Height from base to summit of third radials, 0-65 inch ; do., to top of vault. 

 0'95 inch ; breadth (across between the arms) 0-91 inch ; breadth of base 0-42 

 inch ; height of do., 0-12 inch. 



Locality and position. Cedar Creek, Warren County, Illinois. Burlington 

 Limestone of lower carboniferous series. 



Actinocrinds asteriscus. Body about medium size, depressed or subdiscoidal, 

 rather more convex below than above the arms ; calyx expanding rapidly from 

 the base about half way up, then flaring outwards so as to bring the third ra- 

 dials and succeeding pieces nearly upon a horizontal plane, composed of thin, 

 nearly smooth flattened plates, which are joined by close fitting sutures; sum- 

 mit much depressed, consisting of numerous medium-sized, convex plates, and 

 provided with a subcentral proboscis ; interradial spices deeply excavated, so as 

 to give the body a distinctly pentalobate outline, as seen from above or below. 

 Base small, apparently rounded and destitute of a marginal rim, about threo 

 times as wide as high. First radial plates wider than long, expanding from below 

 to the lateral angles, three of them hexagonal, and two heptagonal, the angle at 

 the middle of the base of the latter being very obtuse. Second radials small, 

 about twice as wide as long, hexagonal and pentagonal. Third radials slightly 

 larger than the second, pentagonal, or occasionally hexagonal about twice as 

 wide as high, and each supporting on its superior (or more properly, outer) 

 sloping sides, two secondary radials ; these are each succeeded by another, 

 which in its turn, supports two of the first brachial pieces, making four arms 

 to each ray, or twenty in the whole series, all of which seem to rise vertically 

 from the point of attachment. 



The first anal piece is small, longer than wide, hexagonal, and supports on 

 each superior lateral edge a small pentagonal piece, and on its truncated 

 upper end a long, narrow, irregular plate, which extends up and curves 

 inwards with its superior extremity between two of the crown plates. On each 

 side of the latter there is a large irregular curved piece, belonging, probably, 

 to the anal series. The first interradial plates are larger than the first anal 

 piece, and as wide as, or wider than long, hexagonal or heptagonal, and each 

 supports on its superior lateral sloping edges smaller pieces, above which 



1860.J 



