98 PROCEEDINGS OF THE ACADEMY OF [1887. 



thei'efore those of Stephanocrwus, as homologous with the large 

 calyx interradials of the Cyathocrinidae, a view in which we 

 entirely concur, as we have explained on p. 10. But in applying 

 this name to the five plates which form the ventral pyramid and 

 cover the mouth of Stephanocrinus, and also of Haplocrinus and 

 AUagecrinns, as they do in their latest publication, they seem to us 

 to be going very mvich too far. We regard the five summit plates 

 of all three genera as truly homologous with the orals of the 

 Pentacrinoid larva. They cover the mouth and the origin of the 

 ambulacra, just as the orals do in the Neocrinoid; and this relation 

 is not characteristic of the calyx interradials in any Pehnatozoon 

 whatever. It is only in the Cyathocrinidae and in the Blastoids 

 that these plates have any close relation to the mouth at all. But 

 they do not cover it and shut it oft' completely from the exterior as 

 the summit plates of Stephanocrimis and AUagecrinus do." 



We have been more than once charged by Dr. Carpenter with 

 inaccurate statements as to his views, and in some cases w'ith reason 

 as we have admitted; but we do not believe we have ever been 

 chargeable with anything so completely unfounded as the foregoing 

 criticism. It is based entirely upon the single remark of ours on 

 page 46 (Revision Palaeocr. Pt. Ill), that "the ventral pyramid in 

 Haplocrinus and Coccocriuus is composed of interradials and not of 

 orals, and the same may be said of Stephanocrinus."^^ This was 

 written under the supposition, then entertained by all Palaeontolo- 

 gists, perhaps watli the exception only of Etheridge and Carpenter, 

 whose interpretation will be quoted presently, that Stephanocrinus 

 was constructed of only three ranges of plates, and we considered 

 the third row, constituting the whole portion from the coronal 

 processes inward, to be interradial plates. Messrs. Etheridge and 

 Carpenter^ in 1888, interpreted all plates, in common with the 

 deltoids of the Blastoids generally, and the interradials of the 

 Cyathocrinidae, as orals, a view which they have since abandoned. 

 In the same paper p. 239 they mention five plates in the summit, 

 composing, according to Hall, a central "proboscis," and say that 

 they have "only seen this proboscis in one specimen," and regard it 

 as "a vault of a few pieces covering in the peristome." This shows 

 clearly that they did not themselves at that time consider these 



*We even did not use the term "ca/yx interradials" in tiiat quotation, we 

 simply spoke of the '^HnterradiahP 



1 Ann. and Mag. Nat. Hist. Apr. 1883, pp. 225 to 246. 



