Mr. 1". P>. Mci-k ('/( thf Ginnit Lirlicnoiiiiiiis. ;}4.'J 



length of this appendage can l>e seiMi attacliLd to the tlisk at 

 one end, it tapirs oH' until it l)eeonK's exceedingly slender at 

 the free hrukcn end. This character of its termination, espe- 

 cially when viewed in connexion with its length, slenderness, 

 and otlu-r characters, would seem to be a strong objection to 

 the conclusion that it is a ventral tul)e or proboscis. Htill there 

 might have been a minute opening at the extremity, closed by 

 diminutive pieces, as we often see is the case with the opening 

 of much larger crinoids. 



AN'liile examining the specimens of this type, several solu- 

 tions of the mystery of its structure suggested themselves, the 

 first one of which was, that })ossibly the disk, viewed as the 

 body, might really be only a ])eculiarly constructed root or 

 base of attachment of a crinoid, the body of which grew at 

 the free end of the long column-like appendage. This sug- 

 gestion derives some support from the fact that the disk, al- 

 though usually growing on the Hat surfaces of shells &c., is 

 sometimes found growing upon the side of the columns of 

 other, h<rger crinoiils, as well as on other imevcn surfaces ; and 

 in such cases it is bent around to conform to the curve of the 

 surface of attachment, just as we see in crinoid-roots similarly 

 situated — while its Avhole interior is so filled with radiating 

 lamella? as to leave extremely little, if any, space for the vis- 

 cera of an animal, and is, as already stated, apparently her- 

 metically sealed, excepting the minute canal leading \\\i into 

 the long appendage. It is true that the roots of crinoids are 

 generally formed of thickened and ancliylosed rings or seg- 

 ments of the column ; but Mr. Billings has figured the root of 

 one type {Cleiocrinus grandis), apparently composed of an 

 accidentally folded expansion of minute polygonal ]ilates 5 and 

 it is worthy of note that the column attached to this root is 

 hmgitudinally divided by five sutures. It is also true that 

 there is no example, so far as known to the writer, of any such 

 system of radiated lamellae being connected with the root of a 

 crinoid ; but this objection would doubtless apply wnth even 

 greater force against the conclusion that this disk is the body 

 of one of these animals. 



On the other hand, among the strong objections to the sug- 

 gestion that these disks are roots, may be mentioned their very 

 regular symmetrical form, and the fact that no indications of 

 a body at the free end of the column-like appendage have yet 

 been observed, nor of a detached body with adhering portions 

 of a column agreeing with this ; while no free crinoid that 

 might have been attached to this column in its early stages of 

 growth is known in these rocks. In addition to this, the 

 tapering and pointed extremity of this appendage would seem 



