1886.] NATURAL SCIENCES OF PHILADELPHIA. 125 



arm joints were shown, that from appearances there had been no 

 others, and that these formed, in all probability, " merely upward 

 prolongations of the radials." He states further that the " more 

 or less obscure furrow," seen by Wetherby upon the outer surface 

 of each arm, was in reality a recurrent ambulacrum, and that in 

 his opinion the relations of Hyhocystites are rather with the Blas- 

 toids and " Crinoids than with the Cystids." Upon the latter 

 point we cannot agree with him, although we admit that there are 

 recurrent ambulacra in all five rays. We think, like Wetherby, 

 that the ambulacra resemble decidedly those of the Cystids, and 

 not those of the Blastoids. Hyhocystites evidently had no hydro- 

 spires and no hj'drospire pores, and the ambulacra, contrary to 

 any of the Blastoids, extend beyond the radials down into the 

 basals. Neither has it calicine pores, nor pectinated rhombs, and 

 hence cannot be a Cystid, even if it has appressed ambulacra, 

 which, we think, take the place of true arms. 



Among the specimens from the Canada Survey Museum, which 

 we had the good fortune to examine through the kindness of Prof. 

 Whiteaves, we examined the type of Lecanocrinus elegans Billings 

 ( Taxocrinus elegans W. and Sp.), one of the earliest of all known 

 Crinoids, and which seems to be destined to throw light upon the 

 peculiar ambulacra of Hyhocystites. This beautiful and well- 

 preserved specimen has upon the outer or dorsal surface of its free 

 arms, upon each one of them, from their tips as far down as the 

 top of the secondary radials, in addition to their regular ventral 

 farrows a recurrent dorsal furrow, such as is found in Hyhocys- 

 tites upon the calyx, and dorsally and ventrally upon the two arm 

 joints. These dorsal furrows are indistinctly represented by 

 Billings in Decade iv, PI. 4, fig. 4 a, although in the specimen 

 they are well defined, and it appears as if they had been lined by 

 a double series of alternating plates. Such dorsal furrows have 

 since been identified also in the tj^pe of Taxocrinus Isevis by 

 Walter R. Billings. That these furrows are continued from the 

 ventral side, and as such form a part of the ambulacra, cannot be 

 doubted, and is further proven by the fact that the furrows 

 diminish in width as they descend the surface of the arms. In 

 these species the regular furrows of the arms probably were not 

 sufficient to supply the animal. This was certainly the case in 

 Hyhocystites, which in two of its ra3^s has no brachial appendages 

 whatever, and these consist in the three other rays of but a few 



