288 Bibliographical Notices. 



grooved but imperforate radials. In the early Pentacrinoid larva 

 the axial cords lie not within but on the ventral surface of the basals, 

 radials, and brachials, " which are then mere flat plates ; by an 

 endogenous thickening of the calcareous network of those plates the 

 axial cords come to lie in furrows channelled out in their ventral 

 surfaces ; while by a further endogenous growth of that network 

 these ventral furrows are completed into canals, and it is by a still 

 further endogenous thickening that these canals finally come to 

 occupv the centre of each calcareous segment " *. This has been 

 pointed out over and over again of late years, and it has been 

 shown that each transitory condition of the Neocrinoid is a perma- 

 nent one in certain Palseocrinoids. But according to the reasoning 

 employed by Wachsmuth and Springer the early Pentacrinoid has 

 no dorsal nervous system, because its radials are not " pierced by 

 canals." Furthermore, the arm-joints of many, if not all, Camarata 

 contain canals which all converge on the grooves of the- radials. 

 Were there no axial nerves within these canals ? Apparently not ; 

 for it is suggested that " the entire nervous system was located at 

 the oral side." If there were any real grounds for supposing this 

 to have been the case, it would be necessary to remove the Camarata 

 from the Crinoids altogether and to establish another class of Pelma- 

 tozoa for their reception. ^Ye believe that a much more satisfactory 

 explanation may be given of these grooves upon the inner surface of 

 the vault of the Actinocrinites than that suggested by the authors, 

 who do not seem to have sufficiently considered the difficulties into 

 which it would lead them ; and we shall be much surprised if they 

 do not withdraw it in the concluding section of the ' Revision.' 



We may be permitted to express the hope that a little more care 

 will be exercised in correcting it for the press than has been given 

 to the one under review. References to wrong and even to non- 

 existent plates and the misspelling of specific names might have been 

 avoided. There are three mistakes on p. 127 alone, while such 

 errors as " Platynicridaj " and the statement on p. 41 that the anus 

 of Coccocrinus and Culicocriims " is located between the first and 

 second radials" ought not to have escaped notice. Others of a 

 similar kind have been already mentioned incidentally. The reader 

 must also be cautioned against misunderstanding the authors' very 

 free use of the word " evidently " when discussing controverted 

 questions. It is employed as a short version of " in our opinion ;" 

 as, for example, in the passage respecting AlJaf/ecrimts on p. 33, 

 which we have quoted above ; the statement on p. 58 that the 

 interradials of Haplocrinus " evidently separated in the growing 

 animal and the oral plate moved outward ;" and another on p. 55 

 that the underbasals of Steminatocrinus are " evidently fused toge- 

 ther to a single piece." 



Space does not permit our noticing many other morphological 



points in which we altogether disagree with Messrs. Wachsmuth and 



Springer ; and we cannot help thinking that in some cases, besides 



that of the underbasals, they have committed themselves to gene- 



* W. B. Carpenter, Proc. Roy. Soc. 187G, p 454. 



