SPENCER NIAGARA FOSSILS. 603 



Lingula ill gens ^ n. s. 

 Discina clara, n. s. 

 Cratita anna, n. s. 

 Pleurotomaria clifeiformis, n. s. 

 Cotiularia magtnjica (Spencer, 1879). 

 Co?iularia nigosa, n. s. 

 Cotiularia wt'lkinfi, n. s. 

 Orthoceras bartonense, n. s. 

 Cyrtoceras reversum, n. s. 

 Lituites niagarensis, n. s. 



Pal^aster granti, nov. sp. 

 Plate 7. Fig. 1. 



Body stellate and small with short arms, about two centimetres 

 across ; disc less than one centimetre wide, and apparently formed 

 by the junction of the rays; rays five millimetres wide at base, 

 tapering slowly, and terminating in rounded extremities, at about 

 eight millimetres from junction of their base with the disc ; upper 

 surface of rays composed of five ranges of highly convex or tu- 

 berculiform plates (the marginal and ventral rows being the most 

 conspicuous) and separated from each other by minute plates 

 (becoming fewer on approaching the extremities of the rays. 



The ellipsoid marginal tuberculiform plates number about 

 twelve for each complete side of the rays, and the central range is 

 composed of a similar number, but in form these plates are moie 

 circular. The disc between the terminal central row of plates of 

 the rays is crushed and structureless, except a slight elevation in 

 the centre. The terminal plates of the marginal series are larger 

 than the others of the range. The madreporiform tubercle is of 

 a spherical form and relatively large, being nearly two millime- 

 tres in diameter, and is situated at the axil of two rays. Both the 

 tuberculiform plates and the madreporiform tubercle have a horny 

 granulated surface. 



The ventral side is unknown. Only two specimens have been 

 obtahied, and of the more perfect two rays are broken away, al- 

 though the whole of the disc is present. 



This elegant species is easily distinguished from both P. nia- 

 garensis and Petraster btUulus by the relatively short arms, and 

 smaller number of radial plates, although the upper sides of these 

 species are unknown. 



Formation and Locality. —This species w^as discovered by Col. 

 C. C. Grant in the upper Clinton-beds at Hamilton, Ontario. 



iv — 4 — 4 [May, 1SS4. 



