94 



in the Geology of Illinois, vol. ii, p. 188, fig. 5. The specimen is thir- 

 teen lines in diameter, the ambulacral centre thirteen lines from the 

 anterior margin, and the mouth eleven lines. * 



Gli/ptocrinus armosus (McChesney, sp.). — This extraordinary Crinoid 

 is figured by McChesney in his New Pal. Foss.", pi. 7, f. 6, and also 

 by Prof. Hall, in the 20th Reg. Rep., N.Y., pi. 10, f. 11. The speci- 

 mens are between two and three inches in length. There are ten arms, the 

 anterior side is much inflated, the proboscis appears to be large at its 

 base and excentric in its position, but instead of standing erect, it bends 

 down to the surface of the vault, and lies upon it, crossing over to the 

 posterior margin. Judging from the figures, the centre of the base of 

 this organ must be distant from the radial centre at least one-fourth of 

 the whole width of the vault. G. Siplionatus (Hall), figured on the 

 same plate, shows, that the anterior grooves curve round to the 

 posterior side of the proboscis, as they do in B. ieosadactylus above 

 cited. 



I should also state here that two or three years ago, Mr. Meek, to 

 whom I had written for information on this subject, wrote me that in all 

 cases, where he had observed the grooves on the interior of the vault, 

 they radiated, not from the mouth, but from a point " in front of it." 

 (This would be not in front of, but behind the mouth, according to the 

 terminology used in these notes. I think that the side in which the 

 mouth is situated should be called " anterior " or " oral/' even although 

 both the mouth and anus should be included in it.) 



* la April last I received from Messrs. Meek and Worthen a paper entitled, "Notes on 

 some points in the structure and habits of the Paleozoic Crinoidea." Of all the papers 

 relating to this subject yet published on this continent, this one, at least so it appears to 

 me, is the most interesting and important. It is written with a clearness and particularity 

 rarely to be seen in paleontologieal memoirs. In some respects it confirms the opinions 

 advocated in these notes, but bears directly against my views on the question here under 

 discussion, i.e. — " the position of the mouth with relation to the radial center." As I wish 

 to give the remarkable observations of the authors full consideration, I shall not discuss 

 them now but delay until the September No. of this Journal. I shall only state here, that 

 I believe that the grooves on the ventral disc of CyathocrinuSj and, also, the internal " con- 

 voluted plate" of the Paleozoic Crinoids, with the tubes radiating thereform, belongto the 

 respiratory and, perhaps, in part, to the circulatory systems — not to the digestive system as 

 is supposed by the authors. The convoluted plate with its thickened border, seems to for- 

 shadow the " sesophageal circular canal " with a pendant madreporic apparatus as in the 

 Holothuridea. To me the final determination of this question is of much importance, for, 

 if Meek and Worthen are right, then I must be wrong so far as regards nearly all that I 

 have published with reference to the functions of the apertures of the Paleozoic Echinoder- 

 mata. It is fortunate that the solution of this curious problem is now undertaken by men 

 who have access to the magnificent cabinets of the geologists of the western States, and 

 also by men who habitually discuss scientific subjects with the sole object in view of arriv- 

 ing at the truth. 



