100 PROCEEDINGS OF THE ACADEMY OF [1887. 



erable surprise to us that in both these publications we should be 

 held up to criticism for a statement which we did not make in any 

 such form as their language would imply, and that the authors 

 should indulge in a general adverse comment upon our incidental 

 remark on Stephanocrimis, without the slightest intimation of the 

 very important additions to our former views consequent upon new 

 discoveries, which would have made our meaning entirely clear. 

 These were published in Part III, Revision of the Palaeocrinoidea, 

 pp. 282-290. 



To represent us as arguing that the plates which we recognize as 

 calyx interi'adials "cover the actinal center," or "cover the mouth 

 and the origin of the ambulacra, " seems to us very much like 

 setting up a man of straw for the pleasure of knocking him down. 

 For our whole argument in favor of a homology of the orals of the 

 Neocrinoid with the central plate in Palaeocrinoids, has been ex- 

 pressly put upon the ground that the latter plate covers the actinal 

 center ; and one of the strongest objections we have constantly urged 

 against such a homology with the proximals, has been that they do 

 not (Rev. Pal. Pt. Ill, p. 53). Etheridge and Carpenter add in 

 continuing their criticism above noticed : " There is not a single 

 Crinoid known in which plates which are universally recognized to be 

 calyx interradials cover in the actinal center." Of course not ; and 

 we do not know of anybody who says they do. But on the other 

 hand it is equally true that there is not a single Palaeocrinoid known 

 in which the plates that are universally recognized as orals cover 

 the whole ventral surface; and upon this ground we might well contend 

 that if the plates which Etheridge and Carpenter consider to be 

 orals are really such, then Allagecrmus and Haplocrinus are Neo- 

 crinoids, in which from the larva to the adult, as a rule the whole 

 ventral surface is covered by actinal structures. Their statement 

 above cited, as to the homology of plates which "cover the mouth 

 and the origin of the ambulacra, just as the orals do in Neocrinoids," 

 might be profitably ajiplied to the case of Car-yocrinus, as shown 

 by a number of excellent internal casts recently obtained from 

 Racine, Wisconsin. CaryoGrinua has a large central piece, and 

 this is surrounded usually by eight plates, which are arranged in a 

 totally different manner from the so-called pi'oximals of the Palaeo- 

 crinoidea. Three of them are radial, the others interradial, (figs. 6- 

 7). The interradial pieces alternate with the radial ones, one to 

 each side, except at the anal interradius where three smaller pieces 



