Description of Some Xew Species of Fossils. 95 



vtil, and larger, while the iutertubular species are thinner than they 

 are in this species; the direction of the striae On the non-poriferous 

 margin of Hall's species, forms a much larger angle with the edge of 

 the branch than it does in P. ^jereZer/ro?.?. 



Locality and Position. — In the upper part of the Cincinnati Group, 

 near ( "larksville, O. Type specimen found b}' Mr. F. Fornshell. 



OPHIUROIDEA. 



Protastekina, n. gen. 



Rays five, slender, flexible, and extending much beyond a circular 

 and minutely granular disk, which is provided with short, slender, and 

 outwardly directed spines ; iuner ra}^ pieces regularly alternating, of 

 an hour-glass shape, and interlocking along the median line, which is 

 therefore not straight but zigzag; outer ray pieces elongated, directed 

 obliquely outwards, so as to partly overlap each other; two rows of 

 large pores between the inner and outer ray pieces; in the type species 

 these pores appear to have been occupied b}^ loosely-fitting, sub-pvra- 

 midal plates, some of which have a deep depression in the top, as 

 though they were perforated; their true nature, however, is very un- 

 certain. Oral pieces ten, each pair being formed bj- two of the outer 

 raj" pieces. 



Type, P. fmbriata. 



This genus is allied to Protaster, of Forbes, but differs from it in the 

 following particulars : 



1. The disk of Protaster is composed of distinct imbricating plates, 

 which carry no spines. 



2. The inner ray pieces do not interlock, but are set opposite to 

 each other, with the impressed mesial line straight. 



3. The oral plates are formed by the extension of the inner ray 

 ossicles, and not of. the outer ray pieces. 



4. That genus has four rows of pores, while in Protasterina there 

 are but two rows. 



The rays of Tjieni aster, of Billings, bear some resemblance to those of 

 Protasterina, but in that genus there is no disk, and the ambulacral 

 ossicles are set opposite to each other, while the two rows of pores are 

 situated within those pieces. Mr. Billings placed his genus with the 

 Asteroidea, while Protasterina clearly has the characters of theOphiu- 

 roidea. 



Protaster fijibriata, n; sp. (Plate IV., fig. 9, da, 9b and 9c.) 



Disk of medium size, circular. Dorsal side of disk, and rays to mar- 

 gin of disk, covered with a granular integument. Ventral surface of 



