484 Mr. F. A. Bather on some 



[Rev. III. (p. 196), Proc. 1886, p. 120] : "it is probable 

 that one of the non-armbearing so-called radials [in Baero- 

 crinus] represents an azygous plate, such as we find in most 

 of the Fistulata, that the right posterior radial and the anal 

 plate were as yet undeveloped, and that Baerocrinus had but 

 four radials. This interpretation of the plates, it seems to 

 us, is corroborated by the gradual disappearance of the 

 azygous plate among allied forms in palgeontological times, 

 and by the contemporary increase in the dimensions of the 

 right posterior radial and the anal plate. The two latter 

 pieces were absorbed from the azygous plate : at first the 

 posterior radial, which in Hoplocrinus took the right upper 

 corner, the left side remaining intact j afterwards in Hybo- 

 crinus the anal piece, which absorbed the left corner of the 

 plate also." This seems quite clear ; the azygos plate is 

 absorbed in Hoplocrinus and Hybocrinus. 



But the footnote on the same page is even clearer. The 

 anal of Antedon and the azygos of Baerocrinus " both agree 

 .... in being absorbed by other plates ; the azygous plate 

 palgeontologically by the right posterior radial and anal plate, 

 the other in the growing animal over the whole surface." 

 Now this means that in the evolution of the Fistulata the 

 plate in the successive genera homologous with the azygos 

 of Baerocrinus was gradually absorbed by the radial and 

 anal. 



But why mention Baerocrinus at all? 



On p. 40 of Revision III. (Proc. 1885, p. 262) Wachsmuth 

 and Springer say " In our chapter on the radials we have 

 already alluded to the azygous piece, and expressed our con- 

 viction that its gradual resorption gave origin, not only to 

 the right posterior radial, but also to the anal plate." Why, 

 let me ask Messrs. Wachsmuth and {Springer, did they omit 

 all reference to Baerocrinus in this passage? Presumably 

 because this perpetual insertion of the name Baerocrinus 

 would make nonsense ; for they cannot mean to say that the 

 anal of the Carboniferous Scaphiocrinus iowensis has absorbed 

 part of the azygos of the Ordovician Baerocrinus Ungerni. 

 When did it cross the Atlantic to collect fossils in the Brand- 

 schiefer of Err as ? 



Again I said (p. 324) : " (3) Anal of Antedon not homolo- 

 gous with any plate of the Fistulata but an embryonic inter- 

 radial." This statement of their views is they say (p. 390) 

 " more faulty yet. To agree with Pt. ill of the Revision 

 it should be amended as follows : Anal plate of Antedon 



