436 



DR F, A. BATHER. 



not a diagnostic character. Further, it is difficult to accept Dr Jaekel's view of it 

 (1899, p. 214) as more primitive than a normally convex base. 



§ 293. The composition of the theca presents no particular difficulties in the three 

 lower circlets, and here Dr Jaekel and I are agreed. Circlets IV. and V., however. 



*^ ^ / \ 13> ^-^ \ / ''y 



Text-fig. 40 bis. — Analysis of Cheirocrinus penniger, as in Bather (1900), repeated for 

 comparison with text-fig. 41. 



are subject to so much variation that their interpretation is not easy. In 1900 (p. 63, 

 f. xxxii.) I gave an analysis of Cheirocrinus penniger based on the work of Fr. Schmidt 

 (text-fig. 40 his). Dr Jaekel's analysis (1899, p. 196, f. B ; our text-fig 41) agrees with 



Text-fig. 41. ^Analysis of Cheirocrinus penniger, after Jaekel (1899). To construct this diagram, the 

 outlines of the plates have been traced from .Jaekel's figure, but all have been spaced out, and those of 

 the right anterior radius and interradius and of the anterior radius have been moved to tlie right-hand 

 side of the diagram. By this means, and by the substitution of numbers 1-24 for the symbols of Jaekel 

 (cf. text-fig. 37), the diagram is rendered comparable with text-fig. 40 his. The numbers " 18 (or 24 or 23) " 

 and " 24 (or 18) " refer to the plates immediately below them. The alternative numberings are explained 

 in the text. 



this in the form and position of all plates numbered by me 1 to 19, or even, if allowance 

 be made for my addition of the side-plates, up to the deltoid plate 22. Plate 23, the 

 posterior deltoid, is placed by Jaekel above the suture between 17 and 18, and this, 

 morphologically considered, is undoubtedly preferable to its position in my diagram 

 above plate 18. The plate which I have numbered 24 does not appear at all in 



