REVISION OF PALEOZOIC STELLEROIDEA. 187 



URASTERELLA (?) ASPERRTMA (Salter). 



Palseaster asperrima SALTER, Ann. Mag. Nat. Hist.,ser. 2, vol. 20, 1857, p. 325, 



pi. 9, fig. 1. WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 



(Palseontogr. Soc. for 1861), 1862, p. 24, fig. 15 (1). 

 Palseaster asperrimus SALTER, Mem. Geol. Surv. Gt. Britain, vol. 3, 1866, p. 289, 



pi. 23, fig. 2. 



Palseaster (?) asperrimus STURTZ, Palseontographica, vol. 32, 1886, p. 91. 

 fTetraster asperrimus NICHOLSON and ETHERIDGE, Mon. Silurian Foss. Girvan 



Dist, Ayrshire, fasc. 3, 1880, pp. 320, 321, 324. 

 Salteraster asperrimus STURTZ, Verh. naturh. Ver. preuss. Rheinl., etc., vol. 50, 



1893, pp. 43, 60. 



Nicholson and Etheridge wrote of this species as follows: It 

 "is an unsatisfactory species. The specimens in the Museum of 

 Practical Geology have the large transverse ossicles very apparent; 

 but as to whether there is a row inside or outside these, or both, 

 we are by no means certain. It appears, however, to have possessed 

 only four rows." Under Tetraster they compare this species with 

 their "T. sp. ind.," which is a true Urasterella (U. girvanensis) . 



It seems best under these circumstances to refer this species to 

 Urasterella, it being apparently near U. grandis. It is found in the 

 Caradoc or Baia sandstones (Ordovicic), near Welshpool, North 

 Wales. Should it prove to be generically different from Urasterella , 

 then the name Salteraster Stiirtz can be revived, as he names P. asper- 

 rimus as the genoholotype. 



URASTERELLA (?) CONSTELLATA (Thorent). 



Asterias constellata THORENT, Me"m. Soc. ge"ol. de France, vol. 3, 1838, p. 259, 

 pi. 22, fig. 7. 



The original figure of this species does not permit of determining 

 its generic position. It is described as having but one range of plates 

 on each side of the ambulacral grooves, and the figure seems to 

 indicate the presence of a large disk with well-defined interbrachial 

 arcs. It seems to have more of the characters of Urasterella than 

 of any other genus. 



The specimen was found in the Siluric ( ? Lower) strata in northern 

 France (Mondrepuis, L'Aisne). 



URASTERELLA RUTHVENI (Forbes). 



Uraster ruthveni FORBES, Mem. Geol. Surv. Gt. Britain, vol. 2, pt. 2, 1848, p. 436; 



Mem. Geol. Surv. United Kingdom, dec. 1, 1849, p. 1, pi. 1, fig. 1; in McCoY, 



British Pal. Foss!, 1851, p. 59. MURCHISON, Siluria, 1854, fig. 39-3. 

 Palxaster ruthveni SALTER, Ann. Mag. Nat. Hist., ser. 2, vol. 20, 1857, p. 326. 



WRIGHT, Mon. British Foss. Echinod., Oolitic, vol. 2, pt. 1 (Palaeontogr. 



Soc. for 1861), 1862, p. 25. 

 Urasterella ruthveni FORBES, in McCoY, British- Pal. Foss., 1851, p. 59. 



This, the genotype of Urasterella, is unfortunately not well known, 

 but appears to be congeneric with U. grandis and U. pulchella. It 

 occurs in the Upper Ludlow beds (Siluric), near Kendal, Westmore- 

 land, England. 



