FOSSILS OF THE BURLIXGTON GROUP. 351 



prominence on each of the first and second radials is 

 pinched out so as to form a prominent sharp, transversely 

 arranged ridge, while on each of the smaller plates it is a 

 rounded, rather pointed node, the whole presenting a very 

 rough appearance. 



Hight of body to the horizon of the arms, 0.74 inch; 

 do. to top of vault, 0.88 inch; greatest breadth at top of 

 third radials, 0.80 inch. 



In general form and surface markings this species resembles the fol- 

 lowing, but its body is more spreading above, and it has ten or more 

 arms less, while its vault is much more depressed and provided with a 

 proboscis. It seems to bear much the same relations to the section (b) 

 of the genus Strotocrinus that the subgenus Physetocrinus bears to the 

 typical forms of Strotocrinus. 



Locality and position Burlington Limestone of the Lower Carbonif- 

 erous, at Quincy, Illinois. 



SUBGEXUS PHYSBTOOKDOJS, M. and W. 



STROTOCBIXUS (PHYSETOCRIXUS ?) ASPER, M. andW. 



PL 7, Fig. 1. 

 Strotocrinu* ( Phyeetoerinus f) asper, MEEK and WOBTHEX. Proceed. A cad. Sat. Sci., Phila., 1869, p. 181. 



BODY somewhat urn-shaped, being obconical below, with 

 nearly straight, gradually expanding sides, and rather ven- 

 tricose vault. Base about three times as wide as high, 

 truncated below and angular, though not thickened or 

 properly expanded around the lower margin, which is so 

 broadly and deeply notched at the sutures as to present a 

 trilobate appearance as seen from beneath. First radials 

 wider than high, and as usual two heptagonal and three 

 hexagonal. Third radials of the same size as the second, 

 and bearing on each of their superior sloping sides a some- 

 what smaller secondary radial, each of which bears on its 

 outer sloping side a series of brachial pieces, leading to an 

 arm, while on its inner sloping side it supports a small ter- 

 tiary radial, bearing on its inner side brachial pieces lead- 



