Bibliographical Notices. 41 1 



two alternatives suggested by Wachsmuth and Springer on p. 298 

 the first is preferable, viz. that " the rules which meet with no 

 exception among the Palajocrinoidea, as far as we know, do not 

 hold good for the Neocrinoidea." The American authors, however, 

 elect for their other alternative, and believe that Neocrinoids are 

 reallj- " built upon the plan of dicyclic Crinoids." They are there- 

 fore driven to suggest " accidental " causes to explain away facts 

 which do not suit their theory. 



At the end of the volume are nearly four pages of additions and 

 corrections which apply to all the three parts of the ' Kevision ; ' 

 and wo strongly advise pala3ontologists who wish to use the work 

 to commence by making the necessary alterations in their copies. 

 If this be neglected they will rise from the perusal of some passages 

 with an impression altogether different from that which the authors 

 meant to convey. This is especially the case in those parts of the 

 book which contain discussions of disputed questions, e. g, the syste- 

 matic position of Encrinus, on p. 231, and the composition of the 

 calyx of Stemmatocrinus, on p. 255. We cannot but think that the 

 authors would have been spared the necessity of correcting their 

 statements in these and similar instances if they had taken a little 

 more trouble to give exact references to the writings of fellow- 

 workers wliom they quote. 



This is no doubt an excessively laboiious task ; but prevention is 

 notoriously better than cure, and there is no more certain means of 

 avoiding misquotation than a free use of exact references. ^Messrs. 

 Wachsmuth and Springer have, however, largely dispensed with 

 such references, and we could mention several instances in which 

 the accuracy of their statements has suffered in consequence. But 

 this is a matter of more importance to themselves than to any one 

 else ; while they have done a most valuable service to their fellow- 

 workers by the preparation of a copious index to all three parts of 

 their ' Revision.' It does not appear in the ' Proceedings of the 

 Philadelphia Academy,' where their work was originally published, 

 but has been inserted at their own expense into the numeroiis sepa- 

 rate copies of the concluding section of the ' Revision ' which they 

 have obtained for distribution. The preparation of this index, which 

 occupies thirty-one pages of double columns, must have been a work 

 of immense labour, for which they will receive the heartiest thanks 

 of all students of the Pelmatozoa. The discoverer of a new specific 

 or generic type will now be able to see what names are preoccupied, 

 and he will no longer have any reason for enriching zoological 

 science with new synonyms. That an index of this kind was wanted 

 may be judged from the fact that a new genus Triacrinus, with a 

 tj'pe species T. pi/rifonnis, were described in 1884 by an American 

 palaeontologist, who was unaware that not only the generic, but 

 also the specific, name had been preoccupied by Miinster in exactly 

 the same connexion as long ago as 1839 ! 



Messrs. Wachsmuth and Springer assure us that their index 

 " contains a complete list of all generic and specific names used in 

 connexion with the Palseocrinoidca " (p. 303). We have certainly 



