Mr. F. A. Bather on British Fossil Crinoids. 325 



The other branch continues : — 



(1) Poteriocrinus, Radial nearly normal, Azygos and x of 



about equal size, a plate of the tube, t, sunk into 



dorsal cup (fig. 26). 

 (m) Zeacrimis, Azygos beginning to merge in Radial, x 



smaller and t not so low down (fig. 27). 

 (n) Ceriocrinus, Azygos and x both absorbed, t alone 



remains partly in dorsal cup (fig. 38). 

 (o) Erisocrinus, Azygos and x absorbed, t again risen 



above limits of dorsal cup (fig. 39). 



The later stages from the Homocrinus type downwards, in 

 either branch, will no doubt be generally accepted ; only in 

 a few of the details one might prefer a different interpretation. 

 But as regards the earlier stages and on points 1, 2, and 3, I 

 have to differ entirely. In fact I would almost assume the 

 position originally occupied by Messrs. Wachsmuth and 

 Springer, which, it seems to me, they abandoned for quite 

 insufficient reasons. But before bringing forward any new 

 ideas, it will be better to attack those which at present hold 

 the field. 



The history of this controversy is curiously full of mis- 

 understandings and misrepresentations. I hope that I have 

 made no such mistakes : I have done my best to avoid them ; 

 and Dr. Carpenter, who has kindly looked through the MS. 

 of the present paper, agrees to my account both of his own 

 paper and, so far as he can judge, of the papers by Messrs. 

 Wachsmuth and Springer. In the first place Wachsmuth 

 and Springer turned to the right about in 1883 without 

 giving any reason, and the only discoverable reason is the 

 criticism by P. H. Carpenter. But of this criticism half, as 

 already pointed out, was based on a complete misapprehension 

 of Wachsmuth and Springer's views, while the other half 

 was based on a homology of the Antedoa anal that is denied 

 by Wachsmuth and Springer. The latter authors have 

 therefore still to give some reason for their desertion of a 

 hypothesis that was in its main lines perfectly consistent. 



But, taking things as we find them, let us proceed to con- 

 sider the arguments based on the Antedon-\a.vvn. And first, 

 what is the u anal " of the Pentacrinoid ? It is not an inter- 

 radial ; tor the so-called u interradials " that some observers 

 claim to have seen are only perisomic plates of no morpho- 

 logical importance ; further, it is a most gratuitous assump- 

 tion to make Antedon the only form with an interradial in 

 the anal area while devoid of true interradials in the other 

 interradii. The supposition that the azygos plate exists in 



