CONTRIBUTIONS TO PALMONTOLOGY. 327 



It differs from Palceaster jamesi = Palasterina jamesi* Dana {American 

 Journal of Science, n. s., Vol. xxxv, p. 295), according to the figures given 

 by Prof. Dana in the form of the rays, the marginal plates, and many 

 other important characters. 



Geological Formation and Locality. — In shales of the Hudson River 

 group, Cincinnati, Ohio. From Mr. D. H. Shaffer. 



Pal^aster granulosus,! n. s. 



Body of medium size, fiye rayed ; rays a little more than twice as long 

 as their breadth at base ; obtusely rounded at the extremities. 

 Upper sm-face of rays composed of numerous very small tuberculose 

 or subspinose plates ; the madreporic tubercle large, quite distinct, 

 situated laterally at the base of two of the rays. Under surface of 

 rays composed of a marginal range of small tuberculose plates, about 

 twenty-five on each side in a ray measuring one inch and a quarter 

 from base to apex ; and an inner (adambulacral) range of smaller 

 plates, of which about forty-two or forty- three can be counted on 

 the same ray ; the terminal or oral plates are small, elongate, sub- 

 triangular, in pairs at the base of the adjacent rays. Ambulacral 

 areas composed of a double series of short, broad, slightly curved 

 poral plates (ossicula), each plate marked by a sharply elevated 

 ridge along its entire breadth, commencing on the one plate at the 

 outer posterior angle and terminating on the anterior inner angle, 

 and running in the opposite direction on the adjacent plate. When 

 the outer ridged surface of the poral plate is ground away, the 

 narrow openings or pores are visible between the plates, apparently 

 in two rows in each series, making four ranges of pores in each 

 ambulacral area. (The marginal ranges of pores are obscure, and 

 may only be apparent.) On the under surface, near the bases of the 

 rays, the tubercles bear short spines,some of which are still in place. 



This species differs from P. shcefferi in the form and proportions of 

 rays, the greater number of ambulacral plates, and the form and number 

 of poral plates ; the dorsal surface differs in the numerous short sub- 

 spiniform appendages and absence of longer spines. 



* This is not a Palasterina, having no disc-plates filling up the angles, as in the typical species, 

 and as required in the generic description given by Mr. Salter, and followed by Mr. Billinss 

 Can. Org. Rem., Dec. in, p. 76. 



t See remarks upon this species at the end of this Paper. 



