JVew Orders and New Families in the Class Echinodermata. 225 



The cast of the dome, that covered the calyx, has a height, above the 

 connection between the arm farrows and the interior of the body, 

 nearly equal to its diameter. The cast of the canal leading from the 

 dome to the proboscis is near the size of the column, for a distance 

 about equaling the diameter of the body, when it suddenly and 

 rapidly expands over the top of the interbrachials, to three times its 

 diameter within, or about two thirds the diameter of the calyx, and 

 represents the base of the proboscis. The proboscis is here covered 

 with large hexagonal plates, each of which is a little longer than 

 wide, and which seem to form regular, continuing, upright series, 

 toward the apex of the prolonged proboscis, gradually diminishing in 

 size as the latter contracts. 



The length of the specimen, from the bottom of the calyx to the 

 apex of the proboscis, is 4 25-100 inches; to the top of the interbrachi- 

 als, 2 40-100 inches; to the top of the dome, 1 40-100 inches; and to 

 the top of the cah'x, 90-100 inch. The diameter of the cast of the 

 calyx at the top is 75-100 inch; the greatest diameter through the 

 interbrachials is 90-100 inch, which shows a slight expansion above 

 the top of the calyx, and the diameter of the cast of the base of the 

 proboscis is a full half inch. 



This remarkable specimen was found in the magnesian limestone of 

 the age of the lower part of the Niagara Group, at Pontiac, O. D. 

 A. McCord, of Oxford, in Butler count}-, made several plaster casts of 

 it, from one of which I have illustrated and described the species. It 

 would have been a little more satisfactoiy to have had the original, 

 but the workman who discovered it seemed to value its possession, 

 and as I have had no opportunity to communicate with him, or bor- 

 row it, I have ventured upon the opportunities presented for laying 

 the interesting species before the public. * 



MURCHISONIA "WORTHENANA, n. Sp. 



[Plate IX., fig. 3, natural size.] 



Shell rather below medium size, in this genus, and very wide, the 

 apical angle being about 90 deo. It consists of six or seven whorls* 

 very extremely and sharply angular at the lower edge, and the last 

 one, at half the distance from the angle to the columella, commences, 

 with a gentle slope, to ascend to the suture, which is close up under 

 the keel of the volution above. The angularity increases with each 

 descending whorl from the apex, until the keel ma} T be called a flange, 

 and then an extended flange, slightly curving upward, which, on the 



