CONTRIBUTIONS TO PALEONTOLOGY. 329 



Pal^aster jamesi. 



Fossil listerias : Report of G. Graham, J. G. Anthony and U. P. Jambs to the Western Acad. 



of Nat. Sciences, in American Journal of Science (n. s.), I, p. 441. 1841. 

 listerias anthonii, 1)ana. Manual of Geology, p. 221 (with figure). 1863. 

 Palasterina Q) jamesii, Dana; in Amer. Jour. Science (n. s.), XXXV, p. 295. 1863. 



This species, if we may judge from the figure given, is not a Palas- 

 terina, as it wants the '^plated disc ivMcli Jills up the angles" * an essential 

 character of the genus. 



In the figure in the American Journal of Science, the plates of some of 

 the rays are shown as extending from the ambulacral groove to the 

 margin, while in others they are shown as divided, giving a marginal 

 and adambulacral range, as in Pal^aster; and in the absence of disc- 

 plates, I can see no other reference for the species but to that genus. 



Geological Formation and Locality. — This species occurs in the shales of 

 the age of the Hudson River group, at Cincinnati. 



PALiEASTER (ArGASTER) ANTIQUA, TrOOST. 



Asterias antiqua, Troost; in Trans. Geol. Soc. Penn., I, p. 232, Plate x, fig. 9. 1835. 

 Petraster ( .' ) antiqua, Troost ; in Shumard's Cat. of Pateozoic Fossils, etc., p. 386. 1865. 



Body of medium size, five-rayed; rays flexuose. Marginal range of 

 plates large, somewhat quadrangular, with their outer faces subno- 

 dose: the basal plates of the series single, broadly triangular, with 

 slightly truncated lateral angles ; the obtuse angle of the plate 

 directed towards the axil of the rays. This form of the basal plate, 

 leaves at the base of the marginal ranges and bordered by the 

 adambulacral ranges, a small triangular space which is filled by 

 minute plates or granules ; a character not observed in any other 

 species of this genus. Adambulacral ranges, composed of small 

 plates, which are nearly twice as numerous as those of the marginal 

 range; the basal plates of the ranges are elongate, triangular, in 

 pairs from the adjacent rays. Ambulacral grooves, occupied by a 

 single row of sub-quadrate ossicula, which extend across and alter- 

 nate with the adambulacral plates of each margin: the pores 

 have not been observed. Upper or dorsal surfaces not known, 

 except from a few small plates, outside of the marginal plates, which 

 appear to have been crowded over by pressure. (Perhaps these 

 latter plates may have formed a slight disc between the rays.) 



* Saltjse, Annals and Mag. Nat. History, Kov., 1.857 ; cited by Billings, Decade iii, p. 76. 1858. 

 Cab. Nat. 42 



