280 Bibliographical Notices. 



Messrs. Wachsmuth and Springer have changed their views upon 

 several important points of Crinoid morphologj^ since the publication 

 of Part II. of their ' Revision.' Some of these changes have met, 

 and probablj' always wiU meet, with tlie very general assent of their 

 fellow- workers, such, for example, as the withdrawal of the desig- 

 nation " oral plates " from the caljx-iuterradials of Cyatliocrinus 

 and of the Blastoids. But in one case, perhaps the most important 

 of all, we think that the change is decidedly for the worse. 



Mr. Wachsmuth pointed out in the year 1877 that the interradial 

 " proximal plates " which immediately surround the central plate in 

 the vault of the Camarata correspond in many respects to the basal 

 plates of the calyx. This view was further developed in Part II. (p. 15) 

 of the ' Revision,' which appeared in 1881, and it has been pretty 

 generally accepted in this country. In many species the proximals 

 are surrounded by a ring of radially situated plates, which are univer- 

 sally recognized as representing the calyx-radialsof the abactinal side. 

 In the simpler forms of vault and iu the young stages of the more 

 complex types the central plate is thus enclosed by two alternating 

 rings of plates, the proximal ones being interradial and the distal 

 ones radial. The close correspondence between this arrangement 

 and that of the apical system of a young Urchin or Starfish, and also 

 the calyx of a stemless Crinoid like TJintacrinus, is so striking that 

 Mr. Wachsmuth 's suggestion seemed to throw a flood of light upon 

 the composition of the summit in Crinoids, Blastoids, and Cystids 

 alike. 



Now, however, we are told by Messrs. Wachsmuth and Springer 

 that the proximal dome-])lates are the homologues not of the basals, 

 but of the calyx-interradials of the abactinal side, and that the 

 central plate against which they rest represents an undivided basal 

 disk. But although no one knows better than themselves that the 

 radials of almost every Crinoid rest directly on the basals, they make 

 the following generalization on p. 53 : — " In the summit the cen- 

 tral plate occupies, in relation to the radials, tlie same position as 

 the basals : " and again on p. 56, " Basals and radials, iuterradials 

 and anal plates, are then found to occupy the same position orally 

 as aboi'ally." 



We are sorry to find ourselves iu such direct opposition to the 

 American palaeontologists ; but we do not think they will contradict 

 us when we say that there is not a single Crinoid in which the five 

 (or six) calyx-interradials of the dorsal side occupy an intermediate 

 position between the basals and radials. But unless this were so, 

 not merely in isolated and very specialized genera *, hut in the 

 majority of typical Crinoids, both Palaeozoic and Neozoic, the two 

 statements which we have quoted and the new morphological views 

 which they express cannot btit be altogether at variance with the 

 real facts of the case. 



The position of the calyx-radials, not merely of the Pelmatozoa, 



* Such as Acrocrinus, for example. Many very close parallels to the 

 extremely anomalous forms of summit which occur iu some of the Palaeo- 

 crinoids may he found iu the abactinal systems of Urchins, Starfishes, 

 and Ophiurids. 



