EEVlSIOISr OF PALEOZOIC STELLEKOIDEA. 175 



Distribution. — The species occur in North America and Europe and 

 range from the Ordovicic to the Upper Carboniferous. The following 

 are the known species: 



U. pulchella (Billings), Trenton. 



U. grandis (Meek). Richmond. 



U. Jiuxleyi (BUhngs). ?Chazy. 



U. ulrichi, new species. Lowville. 



U. girvanensis, new species. "Upper Ordovicic of Scotland. 



IJ. (?) asperrima (Salter). Bala of Wales. 



U. (?) constellata (Thorent). Siluric of France. 



U. rutliveni (Forbes). Ludlow of England. 



TJ. Tiirudo (Forbes). Ludlow of England. 



U. selwijni McCoy. Siluric of Australia. 



U. asperula (Roemer). Lower Devonic of Germany. 



U., new species. Ithaca beds. Upper Devonic. 



U. montana (Stschurowsky). Upper Carboniferous of Moscow, 

 Russia. 

 Remarlcs. — McCoy in suggesting the name Urasterella did it in the 

 following words: 



"Before I was aware Prof. E. Forbes had described them it seemed 

 to me that the U. [raster] Rutliveni and TJ. Hirudo, as well the similar 

 American species, might be easily separated from the great star- 

 fishes forming the recent genus Uraster, by their small size and much 

 more simple skeletons, and I had named the genus Urasterella in my 

 manuscript." 



This is all that McCoy did to establish the genus Urasterella, 

 abandoning his manuscript definition on learning that Forbes had 

 described the species as those of Uraster. Salter^ in 1857 paid no 

 attention to this name, although he was the fii'st to recognize and 

 define Palasterina, which McCoy proposed at the same time and in 

 the same manner. It seems that Hall (18G8, p. 332) was the first 

 to revive the name Urasterella and regarded Billings's Stenaster as a 

 synonym by taking his second species, S. pulchella, as the genotype. 

 Hall's remarks are as foUows: "Mr. Salter, apparently overlooking 

 my description of Palseaster niagarensis, has placed both the above- 

 cited European species [ Uraster rutliveni and U. liirudo] under Palse- 

 aster, as defined by himseK; but as it has been shown that this genus 

 has two ranges of plates on each side of the ambulacral groove, these 

 forms can not with proprietj'' be arranged Avith typical Paleeasters. 



" There was the same reason for adopting the generic term Uras- 

 terella as for adopting Palasterina, both of which were proposed by 

 McCoy at the same time, and the typical forms of each were specified. 

 Mr. Salter has for some reason recognized the genus Pala?aster pro- 



'Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 326. 

 50601°— Bull. 88—15 12 



