1^4 SMITHSONIAN INSTITUTION 



PLATE LXIV 

 (All figures natural size) 



PAGE 



Figs. i-io. Onychocrinus asteriaeformis (Hall) 422 



Fig. I. One of the type specimens, anterior view ; showing division of the rays into two main 

 trunks, or rami, with ramules branching only to the outside of the dichotom. Author's 

 collection. 



2. Dorsal view of cotype, with three complete rays preserved. A very mature individual, 



with the rami joined by suture for five ranges of plates above the axillary. Mus. 

 Comp. Zool. 



3. A finely preserved, mature specimen with part of stem attached, and anal tube in place; 



posterior view; rami joined for four ranges of brachials. Author's collection. 



4. Lateral view of specimen with infrabasals separated from basals and fused to the top 



coluranal ; ramules branching. Author's collection. 



5. Right posterior view of a specimen with completely developed interbrachials. Author's 



collection. 



6. Crushed specimen, showing form of posterior basal. Author's collection. 



7. Basal view of specimen with infrabasals in position. Author's collection. 



8. Specimen showing curved distal margin of interbrachials. 



9. Specimen with rami connected for a less distance than in the preceding. Author's 



collection. 



10. Young specimen with rami free from the axillary up, and but a single interbrachial plate. 



Author's collection. 

 Upper Burlington limestone ; Lower Carboniferous. Burlington, Iowa. 



Figs. 11-14. ( ?) Onychocrinus polydactylus (M'Coy) 439 



Fig. II. M'Coy's figure of type: Carb. Foss. Ireland, pi. 26, fig. 7. This is a composite figure, 

 partly restored. See fig. 12. 



12. The principal type specimens from which the foregoing figure was drawn, presumably 



belonging to the same individual ; here placed in their probable relative positions, and 

 the missing plates drawn in outline. Science and Art Museum, Dublin. 



Ballintrillick, Bundoran ; county Donegal, Ireland. 



13. Cotype not figured by M'Coy ; fragment with base and a ray having R + 5 IBr, the last 



not axillary ; showing that there may have been six primibrachs. Same collection. 



County Sligo, Ireland. 



14. Phillips's figure of " Poteriocrinus" egertoni; Geol. Yorkshire, II, pi. 3, fig. 39; probably a 



young individual of this species, and the figure probably incorrect at ends of rays, 

 the pointed appearance of which being due to incomplete removal of the matrix 

 in preparation. Said to be from Enniskillen, Ireland. The. type specimen cannot be 

 found either at London or Dublin. 

 Mountain limestone; Lower Carboniferous. Ireland. 



Fig. 15. Onychocrinus sp 420 



Fig. 15a. Fragment of ramus with bilateral branching of ramules, dorsal view. From the Knob- 

 stone, base of Lower Carboniferous, Kentucky; showing the occurrence of the 

 genus at that horizon. Author's collection. 

 IS&. Side view of same. 



