Reviews — Wachsmuth 8f Springer's Monograph on Crinoids. 419 



been recorded from the Fens. The evidence thus aflforded of the 

 occurrence of three individuals goes far in support of the view that 

 the Pelican was really native to this part of England. 



la E "V I :e "w s. 



I. — Wachsmuth and Springer's Monograph on Crinoids.^ 

 Third Notice. 



THE fundamental plates in a criuoid cup are the five radialia. 

 Oddly enough they are the last of the calycal plates to appear 

 in the development of Antedon, and yet they are the very elements 

 in whose constancy and regularity lies the difference between the 

 Crinoidea and their Cystideau ancestors. Intimately correlated as 

 they are with those characteristic crinoid structures, the hrachia or 

 arras, they are the sole permanent elements of the cup. Other 

 parts may be added to or taken away from, but the radialia, or 

 • ' radials ' pai- excellence, always remain. 



The radials, I have said, are five ; that is, one in each ray. 

 In old days other plates that happened in some genera to be 

 incorporated in the cup along the lines of the radii were called 

 radials ; but such plates are now understood to have been 

 primitively arm-ossicles, and are therefore known as fixed brachials. 

 The recognition of these facts, due to Wachsmuth & Springer 

 and P. H. Carpenter, has enormously simplified the task of 

 description, and has for ever closed the wearisome discussions as to 

 where the arms began in the various genera. 



It must not, however, be supposed that the facts are quite so 

 simple as might appear from the above statement. As our authors 

 express it : " In the earlier Inadunata and Articulata — not in the 

 Camerata so far as observed — the radials are frequently compound, 

 i.e. constructed of two segments or parts, which are closely united 

 by a horizontal suture, and in the organization of the Crinoid count 

 as one plate." For the two halves of such a compound radial 

 Wachsmuth and Springer adopt the terms superradial and infer- 

 radial, proposed by me in January, 1892. The latter term is 

 certainly superior to 'sub-radial,' used by Jaekel in 1895 for the 

 same element, since not only does sub-radial mean a plate below the 

 radial, but it was actually applied to such plates, viz., the basals, for 

 many years by some authors. 



The mutual relations of inferradials and radials, and the varying 

 number of compound radials in the several genera of Inadunata 

 Crinoids, lead our authors, by steps which I do not follow, to the 

 conclusion " that there was a time in the early history of the 

 Crinoids when the arm-bearing section [the superradial] was 

 altogether unrepresented. This was apparently the case in 



1 The North American Crinoidea Camerata. By C. Wachsmuth and F. Springer. 

 ^ Mem. Mus. Comp. Zool. Harvard, vols, xx and xxi, containing 838 pp. and 83 plates. 

 (Camhridge, U.S.A., Maj-, 1897.) For First and Second Notices, see Juue and 

 July Numbers. 



