138 



SMITHSONIAN INSTITUTION 



PLATE LXVI 

 (All figures natural size except where otherwise stated) 



PAGE 



Figs. i-io. Onychocrinus ulrichi Miller and Gurley 425 



(Also on Plates XXI, LXVII and LXVIII) 



Fig. I. The type, after additional cleaning; posterior view. It shows the relatively shorter and 

 heavier rami than in the last species, and a more mature developmental stage, with 

 strong interbrachials between the rami. University of Chicago. 



Indian Creek, Indiana. 



2. A remarkably perfect specimen from Indian Creek ; posterior view. Shows the strong 

 anal tube rising from the outer side of posterior basal, and the perisome connected 

 with it extending far up the rays. Note that the tube, originating on the right side of 

 the posterior basal, first leans to the left impinging upon the left posterior radial, in 

 which by contact and motion of the flexible calyx it produces a vertical groove (see 

 text-fig. 8) ; this does not occur in all specimens. Compare PI. LXVIII, figs, i, 4, s, to 

 show the amount of expansion of which this calyx is capable. 



J. Anterior view of a similar specimen from same locality, showing extent of interbrachial 

 structures and their crescentic margin, rising high up along the rays. Author's 

 collection. 



4. Similar specimen from same locality and collection, with stem attached (only part of it is 



drawn). 

 4a. Diagram of a ramus from same specimen, showing the diminishing size of clusters 

 distally. 



5, 6, 7, 8a, b. A series of successively younger specimens down to fig. 8, which has but one inter- 



brachial and the rami joined by only a part of one pair of brachials. Author's 

 collection. Indian Creek, Indiana. 



6a. Diagram of a ramus from fig. 6, showing the small development of clusters of ramules 

 in young individuals. 



9. Type of Miller and Gurley's O. canionensis, from near Canton, Indiana; representing a 



j'oung form of this species or of O. diversus. University of Chicago. Exact horizon 

 uncertain, possibly Burlington. 



10. A specimen with more slender rays than those from Indian Creek, from equivalent beds in 



Washington County, Indiana. Author's collection. 

 Keokuk Group ; Lower Carboniferous. Indiana. 



