Manual of the Paleontology of the Cincinnati Group. 



135 



side of the groove ; groove very narrow ; dorsal surface probably 

 covered with small granules or bases of small spines, but this is not 

 certainly known. (Proc. Acad. Nat. Sci. Phila., for 1861, p. 142.) 

 Locality. — Oswego, Ills. 



Remarks. — This species is the only one so far referred to this 

 genus from rocks of our group. In his description Meek considers it 

 as related to P. rigidus, the type. The age of the rocks in which it 

 was found is Trenton or Hudson River and it is inserted here in the 

 hope that more information may be secured relating to it. 



Genus 3. — PALASTERINA (McCoy) Salter, 1857. 



Pentagonal, depressed, the arms a little produced, with three or 

 five principal rows of tubercles above, combined with a plated disc 

 which fills up the angles ; ambulacra rather shallow, of sub-quadrate 

 or slightly transverse ossicles, bordered by a single row of squarish, 

 large plates, the lowest of which (adoral adimbulacral plates, Huxley) 

 are large and triangular, having combs of spines. (Brit. Pal. Foss., p. 

 59 (proposed but not described) ; Salter. Ann. and Mag. Nat. Hist., 

 ser. 2, vol. 20, Nov. 1857, p. 324. Billings, Canad. Org. Remains, 

 decade 3, 1858, p. 76 ) 



Remarks. — Two species have been referred to this genus from 

 our region, but as already noted they are said to have marginal plates, 

 which are absent from the present genus. They have therefore been 

 referred to Palceashr and will be found under P. speciosa. (M. and 

 D.) sp. 



Genus 4.— STENASTER Billings, 1858. 



No disc ; rays linear, lanceolate or petaloid ; grooves bordered by 

 solid oblong or square adambulacral plates; oral plates triangu^r, ten; 

 two rows of ambulacral pores ; dorsal side of disc and rays covered 

 with small plates which appear to be tubercular and not closely fitted 

 together. (Canadian Org. Remains, Decade 3, p. 77.) Urasterella 

 McCoy, 1 85 1. Proposed but not described ) 



Remarks. — It has been proposed by Prof. Hall* to adopt the 

 name Urasterella for Stenaster. The argument advanced is that the 

 two genera are equivalent and McCoy's name has precedence. As 

 far as date of proposal is concerned this is so, McCoy's name dating 



* 20th Rept. /. c. p. 289. 



