336 PROCEEDINGS OF THE ACADEMY OF 



selves, with the original types in the possession of others at Burlington and 

 here. 



The fact that Mr. Wachsmuth is the only person (with the exception of oc- 

 casional visitors) that has been collecting at Burlington during the last four 

 or five years, and that during this time extensive excavations have been made 

 in working the numerous quarries and in opening new streets in the Burling- 

 ton rocks, has given him great advantages in collecting; consequently his col- 

 lection may now be regarded as unrivaled in the number and perfection of 

 specimens, as well as in the number of species. 



Mr. Wachsmuth informs us that he also has many duplicates that he is will- 

 ing to exchange for other Crinoids, or to dispose of in any way that may assist 

 in affording him the means of increasing his collection. 



Genus CYATHOCRINITES, Miller. 



As properly restricted to true typical species, such as the C. planus, Miller 

 and C. mammillaris. C. calcaratus and C. bursa, Phillips, the genus Cyathocrinites 

 includes forms with a more or less globose (or perhaps rarely obconic) body, 

 composed of thin pieces, wliich below the vault consist of the basal, subradial 

 and first radial plates, and but a single anal piece that can be properly regard- 

 ed as forming a part of the walls of the body below the top of the first radials. 

 Of true interradials there are apparently none. The base consists of five pieces, 

 all normally of the same form, and alternating with these there are five gen- 

 erally larger subradials, one of which, on the anal side, differs in form from 

 the others, being truncated above for the support of the only anal piece insert- 

 ed between two of the first radials. The five first radial pieces are compara- 

 tively large and alternate with the subradials all around. 



The succeeding radials are all small, more or less rounded, or sometimes an- 

 gular, and always free or form no part of the walls of the body, those of 

 each ray being distinctly separated by more or less wide interradial spaces. 

 The number of these free pieces varies from two to some six or seven to the 

 ray, the number being generally different in the different rays of the same in- 

 dividual. The arms are slender, more or less bifurcating and rounded or some- 

 times angular, and always composed of a single series of pieces provided with 

 a deep ambulacral furrow along the ventral or inner side, and apparenth' with- 

 out tentacula (pinnulje) along its margins. The column is generally if not 

 always round and pierced by a small canal, and not divisible into five sections 

 longitudinally. 



Tlie vault in this genus is always much depressed, never being extended up- 

 ward in the form of a large poriferous trunk, or so-called proboscis, as we see 

 in the typical forms of Poteriocrinus. It is very rarely preserved in the specimens 

 as usually found, but according to Phillips' and Austin's figures of C.plafius it 

 would appear to be provided with a lateral proboscis, or, more properly as we 

 think, anal tube and an apparent central oral aperture. From specimens of C. 

 malvaceits and C. lowensis, however, which we have had an opportunity to ex- 

 amine in Mr. Wachsmuth's collection and have described in another place, we 

 are satisfied that, in these species at least, which appear to be typical exam- 

 ples of the genus, the apparent central opening is closed by vault pieces, in per- 

 fect sjiecimens. These central pieces, however, are more liable to be removed 

 by any accident than the five larger surrounding pieces, because the latter are 

 more deeply inserted, in order to permit the five rather large ambulacral canals, 

 extending inward from the arm bases, to pass over them, or rather along the 

 upper side of the sutures between them, while these furrows pass in imder the 

 pieces forming the centre of the vault, which are consequently less firmly 

 fixed. 



As we have not had an opportunity to examine the original typical speci- 

 mens of C. planus, figured by Phillips and Austin, we of course cannot assert 

 positively that the vault of these types was constructed like that of the Iowa 

 species we have described, but we are strongly inclined to believe such was 



[Dec. 



