NATURAL SCIENCES OF PHILADELPHIA. 143 



pi. 1, f. 3,) from the same locality, will be at once distinguished by its more 

 spreading rays, greater interradial and interbranchial spaces, and particu- 

 larly by its proportionally, smaller and shorter interradial pieces, as well as 

 by haying the latter resting upon the superior lateral truncated sides of the 

 first radials, instead of upon one of the second, while it has no interaxillary 

 pieces as seen in T. inter scapular is It likewise shows some differences in the 

 bifurcations of its arms, after the first division. 



A marked feature in the specimen from which the description was made 

 out, is the extraordinary development of the right margin of one of the se- 

 cond primary radial pieces, by which it is made to fill the entire adjacent in- 

 terradial space. This, however, as already stated, is probably abnormal. 



Locality and position. New Buffalo, Iowa. Hamilton division of the Devon- 

 ian. 



Descriptions of new species of CRINOIDEA, &c , from the Palseozoic rocks of 

 Illinois and some of the adjoining States, 



BY F. B. MEKK AND A H. WORTHEN". 



RADIATA. 



ECHINODERMATA. 



CYSTIDEA. 



Genus COMAROCYSTITES. Billings, 1854. 



Comarocystites, Billings, Canadian Journal, vol. ii. p. 269, 1854; Report Geol. 

 Survey Canada, p. 288, 185(3 ; Decade iii. Canadian Organic Remains, p. 

 61, 1859. 

 "Body ovate, the smaller extremity being the base ; pelvis small, of three 

 plates, above which are from eight to eleven irregular rows of plates, mostly 

 hexagonal; mouth near the summit provided with a valvular apparatus; 

 arms free, grooved, and composed of a single series of joints bearing 

 pinnulse ; ambulacral orifice in the apex between the arms ; celumn round and 

 smooth. The plates of the only species that has been collected present, in 

 some conditions of preservation, a peculiar vesicular structure of their exte- 

 rior surfaces, while sometimes they are solid and smooth." 

 "Generic name Comaron, a strawberry." 



Comarocystites Shumardi, M. & W. 



Body obovate, the summit being more broadly rounded than the lower ex- 

 tremity ; height about one-tenth greater than the breadth. Basal pieces 

 wider than long, irregularly heptagonal and octagonal, extending out hori- 

 zontally from the column, and having, at two of the sutures, small supple- 

 mentary pieces wedged in between, so as to come nearly in contact with the 

 end of the column. Succeeding ranges of plates above, five, very irregularly 

 arranged, and differing in size and form, but increasing in diameter from 

 below upwards, mostly hexagonal or heptagonal in form ; all deeply con- 

 cave on the outside, with prominent sharp carinse at the sutures ; when these 

 angular prominences are weathered or worn, slit-like pores are sen passing 

 through the sutures, which they cross at right angles, being partly common 

 to each of the contiguous plates. Height, 1*50 inch ; breadth, 1-30 inch; 

 greatest breadth of one of the plates next 10 upper range, O-M inch. Arms 

 and openings of the summit unknown. 



This species is nearly allied to C. punctatus, Billings, the type of the genus, 

 from which it may be distinguished by having only five ranges of plates above 

 the base, instead of seven or eight, as well as by the greater size. of the plates 



1865.] 



