FOSSILS OF THE BUBUNGTON <;i;oFP. 



with little openings along each side, though there certainly appear to be 

 only open furrows in the specimens examined. 



It is worthy of note, in this connection, that there certainly are 

 species, agreeing exactly in all other known characters with this genus, 

 that have no open furrow along the outer or ventral side of the arms, 

 which are distinctly seen to be round on the outer side, and show there 

 a doubl. ''f interlocking pieces along their entire length, while 



the tentactila connect along the inner or under side, as the arms are 

 seen hanging down. This is clearly seen to be the case in a beautiful 

 imen of G. typus (=Trem-atocrinus typu*. Hall) in Mr. WACIISMUTH'S 

 collection, and we can scarcely doubt that in this species there is an 

 open furrow on the inner (under) or dorsal side of the arms. If not, 

 the arms must be tubular, in consequence of having the ambulacra! canal 

 enclosed all around, excepting at the points where the tentacula con- 

 nect along each side. 



3. Cyathwiniifs. Miller. Specimens of this genus showing the vault 

 (more properly the ventral disc) have very rarely been seen. In England 

 a few examples have been found, and these have been supposed to 

 show two openings, one central and another lateral : the latter, accord- 

 ing to Prof. PHILIPP.S* and Mr. AUSTIN'S figures, being provided with a 

 slender marginal tube, or so-called proboscis. Some of Mr. "\VACH- 

 sMrTii's specimens, however, of C. malvacem and C. loicentix. Hall, 

 showing the vault, have led us to doubt the existence of a central open- 

 ing in the vault of this genus, when the specimens have this part entire. 

 The specimen of C. nialctiwux shows the remains of the usual narrow 

 lateral proboscis, and also has an opening in the middle of the vault, 

 but from the appearance of this opening, as well as from the structure 

 of the vault of a specimen of C. loirenaix. in which this opening is 

 closed, we can scarcely doubt that it was also closed in the specimen of 

 C. )H(il>'(t<-cnx. when entire. + The remaining parts of the vault of the 

 ('. mali-tii-fii* mentioned consist of only five comparatively large pi 

 alternating with the upper inner edges of the first radial pieces the 

 one on the anal side being larger than the others, and forming the base 

 of the inner side of the proboscis. These five pieces connect with each 

 other laterally, and extend inward some distance, but not so far as to 

 meet at the center, where there is a sub-semicircular opening, nearly as 

 large as that in the remaining base of the proboscis. Along each of 

 the sutures between the five vault pieces mentioned, a comparatively 

 large furrow extends inward from each arm base to the central opening. 

 These we regard as continuations of the auibulacral furrows from the 

 arms, though there is also a minute opening at each arm base, passing 



plate 9. fig. 14, 



