NATURAL SCIENCES OF PHILADELPHIA. 73 



Dr. Shumard has sufigested, in his Catalogue of North Americau Palaeozoic 

 Echinedermata (Trans. Acad. Sci. St. Louis, ii, p. 358, 1866), that the curious 

 genus of Crinoids described by Prof. Hall, in the Report of the Regents, cited 

 above, under the name Cheirocrinus, may be the same type for which Prof. 

 Hall had previously proposed the name Calccocri/ws, in the second volume of 

 the Palaeontology of N. Y. The name Calceocrinus was proposed by him for 

 some subtrigonal pieces of a Crinoid, which, judging from his figures and de- 

 scription, certainly resemble very closely the basal piece of the subsequent- 

 ly proposed genus Cheirocrinm, — so closely indeed, that we are much inclined 

 to adopt Dr. Shumard's suggestion that they may belong to the same type. 

 Still it seems very improbable that Prof. Hall, with the original typical speci- 

 mens of liis Calceocrimts (of which he says many specimens, all agreeing in 

 form, have been found) at hand for comparison, should have been less liable 

 to understand their true relations to his subsequently described type than 

 others, with only his figures and description of Calceocrinus accessible for com- 

 parison, and consequently proceeded to redescribe the same genus under 

 another name, that he had previously called Calceocrinus. 



The synonymy is also unfortunately still farther complicated, by the fact 

 that Prof. Hall happened to select for one of the above mentioned genera, 

 proposed by him, the name Cheirocrinus, which had been used by Eichwald in 

 1856 for a genus of Cystidians. Eichwald's proposed genus seems to be nearly 

 related, as he has stated, to Echino-encriniles, though it is very probably dis- 

 tinct. H' so, then the name Cheirocrinus would have to stand for his type, and 

 could not be retained for that described by Prof. Hall, even if distinct from 

 his Calceocrinus. In that case, to avoid confusion, the form here under con- 

 sideration might be called Eucheirocriniis. 



Until these questions of synonymy can be cleared up, however, we prefer 

 to describe our species, provisionally, under the name Calceocrinus ; although, if 

 the type of that genus is distinct from Chcirocrifnis, and the latter name can 

 stand, they would have to be ranged under it, as they are clearly congeneric 

 with the types for which it was proposed. 



It is evident that this remarkable genus differs so widely from all the other 

 known types, that it must be regarded as belonging to an entirely distinct and 

 unnamed family, which might be called Calceocrinidse, as it is almost a cer- 

 tainty that Calceocrinus, even if generically distinct from the forms here under 

 consideration, would at least belong to the same family, and if they are gen- 

 erically identical, Calceocrinus being the older name, would have to stand for 

 the typical genus. 



Calceocrinus ? Bradleyi, M. and W. 



Body exclusive of the base subquadrangular, with the upper lateral angles 

 obliquely truncated, and the sides rather deeply sinuous, or constricted 

 above the middle ; compressed antero-posteriorly, and rather distinctly con- 

 cave in the central region of the dorsal side below the middle. Lower dorsal 

 plate triangular, and more than twice as wide as high. Dorso-lateral pieces 

 twice as high as wide, presenting an irregular pentagonal outline, with sloping 

 sides above diverging at an angle of about 90 degrees. Upper dorsal plate 

 about half the size of the lower, subtriangular, or nearly semicircular, 

 slightly more than half as long as wide, and scarcely more than filling the 

 notch between the inner sloping sides of the dorso-lateral pieces. Dorsal 

 arm slender, rounded, and composed first of five pieces, the lower of which is 

 expanded below so as to be nearly three-fourths as large as the upper dorsal 

 piece ; while the succeeding pieces are narrow and slightly longer than wide, 

 excepting the fifth one, which is a little wider than the others, pentagonal in 

 form, and supports upon its superior sloping sides two equal divisions, which 

 are slender, rounded simple, and composed of pieces about twice as long as 

 wide. Lateral divisions of the rays (or perhaps, more properly, supports of 

 lateral arms) composed of pieces that are wider than long, and rapidly dimin- 



1869.] 



