1886.] NATURAL SCIENCES OF PHILADELPHIA. 20t 



and in the position of the ambulacra it agrees with the Blastoids ; 

 and j-et it is, as we shall prove, unquestionably a PaljBocrinoid. 



It seems Roemer^ had discovered sockets for the reception 

 of brachial appendages, and probably these sockets and the val- 

 vular covering of mouth and anus induced him to place the 

 genus with the Cystidea. Johannes Miiller, who also regarded it 

 a Cystid, makes the remark: " Nierenformige Warzen am Ende 

 der Strahlen des sternformigen Feldes deuten auf die Gegenwart 

 von Armen hin." Hall, in vol. ii, p. 351 , of the New Yoi^k Report, 

 does not describe the appendages which he had discovered as 

 Blastoid pinnules, but speaks of tentacula attached to the margin 

 along a slight groove in the base of the depressions between the 

 angular processes which ornament the summit of the body. 

 These tentacula or fingers consist of ten branches, each composed 

 of a double series of plates above, but uniting below a series of 

 coalescing plates which have a different arrangement. It seems 

 to us this description does not apply to ambulacral appendages, 

 nor do we think that Hall took the genus to be a Blastoid. On 

 p. 212 of the New York Report he called it a Crinoid, and in 

 1879 he placed it aside of well-known Pal^eocrinoidea. Pictet 

 describes the base as composed of " five subradials," and " five 

 basals," and the mouth as surrounded by " ten tentacles." Du- 

 jardin and Hupe place it among the Haplocrinidse, between Eaplo- 

 crimis and Coccocrinus, and also these writers describe within 

 the radial groove a reniform impression for the reception of an 

 arm, but thought to observe " lames paralleles " along the grooves. 

 They regard, like Roemer, the central pyramid, the mouth, and 

 the lateral aperture an ovarian opening. 



Considering that Hall, Roemer, Miiller, and Dujardin and Hupe, 

 all describe at the outer end of the ambulacral groove a reniform 

 scar for the attachment of an appendage, it is somewhat surprising 

 that Etheridge and Carpenter place the genus among the Blas- 

 toids. They undertake to explain this by Hall's discovery of 

 " ambulacral appendages .... like those of other Blastoids," 

 and give it as their opinion that the reniform scar of Roemer " is 

 nothing more than an infolded radial lip." We stated already 

 that we thought Hall never regarded Stephanocrinus a Blastoid, 



^ We do not possess Roomer's description of Stephanocrinus which 

 appeared in Wiegmann's Archiv for 1850, and know it only from the quota- 

 tions of subsequent writers. 



