408 Bibliographical Notices. 



calyx-interradials and not of orals, a point upon which we differ 

 from them altogether, as already explained*. 



Passing on to the branch " Fistulata,"' we find that it includes 

 the families HyViocriuidae, Heterocrinidaj, Anomalocrinida?, Cyatho- 

 crinidae, Poteriocriuida^, Belemnocrinidoe, Astylocriuidse, together 

 with the Encrimda3, Catillocrinidie, and Calceocriuidae. The 

 first of these comprises the three genera Bcerocrinns, Hoplo- 

 crhiKs, and Ihjbocrinus, together with the problematical Hyhocys- 

 tites, first described by Wetherby as a Cystid and now regarded 

 by Wachsmuth and Springer as a Crinoid of low organiza- 

 tion. The anomalous recurrent ambulacra of this type seem 

 also to occur in two other Trenton Crinoids, Taxocrhms eler/ans, 

 Billings, sp., and T. la vis. "NVe regard this observation as a most 

 important and suggestive one, and shall await further information 

 respecting these very early and somewhat generalized forms with 

 no little interest. 



Except perhaps for the biserial arms of some species, we do not 

 quite understand the reasons which have induced Messrs. Wachs- 

 muth and Springer to transfer the Encrinidae to the Pala3ocriuoidea. 

 Their diagnosis of the family (p. 194) commences as follows: — 

 " Dicyclic. Closely allied to the Poteriocrinidee, but, as a rule, with- 

 out anal plates." The insertion of the words " as a rule ''f is 

 somewhat misleading; for it implies that there are some members 

 of the family in which anal plates do occur. But there is no men- 

 tion of their presence in the authors' diagnosis either of Encrinus 

 or oi Dadocrhms, the only two genera comprised in the family, and, 

 in fact, ihey have never been described ; while Wachsmuth and 

 Springer seem to be in no doubt at all about the presence of inter- 

 radials in Encrinus, though they admit that these, '' owing to the 

 large size of the articular facets, must have been small at any time, 

 and possibly were absorbed in the adult" (p. 259). It appears 

 to us, however, that the mature Encrinus never can have had 

 calyx-interradials of any kind, since there was no room for them. 

 Not only the second and third radials, but also the primary and 

 secondary arm-divisions (when present) were in close lateral con- 

 tact all round the cup, with their apposed sides flattened against 

 one another, just as in many tropical Comatulce. Even if inter- 

 radials had been present in earlier life, as in some Comafidce, and 

 subsequently resorbed, as "Wachsmuth and Springer believe, they 

 must have been situated above and not between the primary radials, 

 which form a perfectly symmetrical pentagon without any trace of 

 interradials resting npon them. Messrs. Wachsmuth and Spriiiger 

 place under Erisocrinus those Encrinus-V\ke Pala3ozoic species " in 

 which a plate of the ventral tube rests npon the radials. In all 

 probability was the latter piece always present in this genns" 

 (p. 255). Erisocrinus is one of the two Palaeozoic Poteriocrinidae 

 which come nearest to Encrinus; but the American anthors regard 



• Antea, p. 403. See also Ann. & Mag. Nat. Hist. March 1886, pp. 

 ii82-284. 



t The italics arc due t(i tlie authors, and not to tlie reviewer. 



