344 NATURAL SCIENCE [May 



self tried to prove the intimate relation existing between Pisocrinidae, 

 Heterocrinidac, and Calceocrinidae. In short, the Larviform and 

 Fistulate types represent grades of structure, and not those funda- 

 mental divergences, on which sub-orders should be based. In a paper 

 on the Inadunata of Gotland I attempted to show that the presence 

 or absence of infrabasals was a far more deep-seated character. 

 So far as I can see the arguments now brought against this are — 

 first, that I was wrong in saying that Cuprcssocriiius and Myrtillo- 

 crinus had no infrabasals (even though I said so with a note of in- 

 terrogation) ; secondly, that I attached undue importance to another 

 character, namely, the horizontal bisection of certain radials. Even 

 if this were to be admitted, it could not substantiate the remark, 

 " All this is seriously in the way of making the presence or absence 

 of infrabasals a svibordinal character." The question is, whether 

 anyone has ever proved a transition from a true monocyclic form 

 (without infrabasals) to a true dicyclic form (with infrabasals), or 

 vice versa. This question is partially discussed in another chapter 

 by Messrs Wachsmuth and Springer, and the answer to it is " No." 

 This is enough to place the character above the varying development 

 of the tegmen. 



In their sub-divisions of the Camerata our authors appear to me 

 to be even less fortunate. I do not propose to discuss the validity 

 of the families, merely that of the larger groups. And at the out- 

 set it must strike everyone as peculiar that the two chief divisions 

 should be into a Typical and a Non-Typical section. Why should 

 one section be more ' typical ' than the other ? The Typical section 

 contains those forms in which the lower brachial and inter-brachials 

 form an important part of the dorsal cup, and includes the Eeteo- 

 crinidae, Thysanocrinidae, Ehodocrinidae, Melocrinidae, Calypto- 

 crinidae, Batocrinidae, and Actinocrinidae. In the Non-Typical 

 section brachials and inter-brachials are but slightly represented in 

 the dorsal cup. The families are Platycrinidae, Hexacrinidae, Acro- 

 crinidae, and Crotalocrinidae. It appears to me that we have to 

 deal here with four quite different sets of crinoids, that have all 

 undergone modification to a greater or less extent along Camerate 

 lines, but that are of quite different origin. The Crotalocrinidae, for 

 instance, I have always regarded as intimately connected with the 

 Cyathocrinidae, although the publication of the proofs accumulated in 

 favour of this view has been long delayed; here I am glad to be in agree- 

 ment with Dr Jaekel. The Platycrinidae and their allies, as I have 

 before this attempted to show, are not far removed from the Mono- 

 cyclic Inadunata, and were developed independently, long after the 

 rest of the Camerata had come into a flourishing existence. As for 

 the latter, is it not reasonable to suppose that the monocyclic Melo- 

 crinidae, Calyptocrinidae, Batocrinidae, and Actinocrinidae, all which 



