108 PALEONTOLOGY OF NEW-YORK. 



Arms corresponding in structure to those of the preceding species ; the 

 plates slightly interlocking along the centre, and rectangular on their 

 outer margins. Armlets opposite and originating at every fifth, sixth, 

 or seventh plate of the arm, composed of a double series of wedgeform 

 plates. Tentacula originating on the outer edges of the plates of the 

 armlets : joints of tentacula nearly twice as long as wide. Secondary 

 tentacula unknown. 

 Column very long; consisting, near the body, of alternating large and 

 small joints ( the larger being the thicker ones) ; and farther from the 

 body, of several thin joints between the thick ones, and sometimes 

 presenting little difference in the thickness or diameter of the ar- 

 ticulations. 



The conspicuous differences between the preceding and this species are the strongly 

 ridged plates of the latter, while in the other they are but inconspicuously marked 

 in the same manner. The first radial plates of M. nohilissimus are proportionally 

 longer than in this species, and the armlets are more closely arranged ; also the 

 column attached to the base consists of numerous thin plates, while in this species 

 the first joints below the base are thicker, with a very thin and scarcely conspicuous 

 one alternating. Of the present species, some ten or more individuals, in various 

 states of preservation, have been seen, and these are all of nearly the same size. 

 Three specimens of M. nobilissirmis have been found, each one having about the 

 same dimensions as those figured. 



Specimens of this species were found at Schoharie some thirty years since; and 

 the first published notice appeared in the Schenectada Reflector newspaper in 1835, 

 where the specimen fig. 1 of Plate iii was figured and designated under the name 

 of Actinocrinus polydactylus. In the same year, in an article in Silliman's American 

 Journal of Science ( Vol. xxvii, p. 363), this crinoid is referred to as the " Stags- 

 horn encrinite.^^ Subsequently, in 1840, Mr. Conrad noticed this fossil as Jlstrocrinites, 

 and in 1841 as AstrocrinUes pachydactylus. In 1843, Mr. Mather published a figure 

 of the specimen, fig. 2, Plate in, from the Cabinet of Union College, under the same 

 name. No description of genus or species has ever been published, so far as I am 

 aware. The generic name Jlstrocrinites cannot be retained, for reasons given under 

 generic synonymy; and in. adopting a new generic designation, I have retained the 

 specific name of pachydactylus, that name having appeared in the Annual Reports 

 on the Geology of New- York and in the Final Report of Mr. Mather : and the 

 reference of this fossil to a described species Actinocrinus polydactylus in the Sche- 

 nectada newspaper cannot impose the adoption of that specific name, as it might 

 have done had the publication been made in a scientific journal. 



