482 FRANK SPRINGER 



detached from the calyx. ^ That is what has happened in the speci- 

 men figured herein (Plate VII, Fig. 20), where the infrabasals have 

 separated from the calyx in this manner. This feature is the result 

 of the general fact, discovered by Wachsmuth and Springer,^ and 

 accepted by subsequent authors, that in the Flexibilia generally the 

 top columnal is not the latest formed, as in the Camerata and most 

 Inadunata, but remains as a persistent proximale. This has been 

 believed to be a fundamental character, evidencing the independent 

 nature of the group — though the proof of its universality is, in my 

 opinion, not complete, and there are apparent exceptions to it. The 

 remarkable example of regeneration mentioned by me in my former 

 paper on this subject,-^ where the calyx of a Taxocrinus was restored 

 by new growth upon the infrabasals and one basal, is strongly con- 

 firmatory of this idea, and suggests that in this group the axial organ 

 as the seat of vitality in the animal, was located very low in the calyx — 

 i. e., within the infrabasals and extending down into the proximal 

 part of the column. 



Homalocrinus, which Angelin founded on a single species, H, 

 parahasalis,^ is of a similar type, but the basals are larger and not so 

 much concealed by the overlapping infrabasals (Plates VII, Figs, 

 9, 10, 11). I was at first disposed to consider it as congeneric with 

 Calpiocrinus, until Liljevall's careful study of the type specimen 

 brought to light a small radianal lying beneath the right posterior 

 radial. Then it occurred to me that this was the condition of cer- 

 tain specimens from the Wenlock Limestone of Dudley, England, 

 which had for a long time puzzled me — and for which in my former 

 paper I had suggested the name Leiocrinus — and that they would 

 fall nicely under Homalocrinus. They accentuate the differences 

 between H. parahasalis and Calpiocrinus, having larger radianal 

 and more prominent basals. I give figures of two of the specimens 

 (Plate VII, and Figs. 12, 13), and propose for them the name Homalo- 

 crinus dudleyensis. So far as I know, these two genera are the only 

 Crinoids in which such a peculiar development of the infrabasals is 

 found. 



There is a notable difference between them in the arm structure — 



I North American Crinoidea Camerata, Plate II, Fig. 46. 



^ Ibid., p. 39. 3 American Geologist, Vol. XXX, p. 97. 



4 Iconographia Crinorde'rum, Plate XVI, Fig. 2q. 



