92 



SMITHSONIAN INSTITUTION 



PLATE XLIII 

 (All figures on this plate are natural size) 



PAGE 



Figs. i-io. Wachsmuthicrinus thiemei (Hall) 329 



Fig. la. The type; a very perfect mature specimen, slightly flattened; has arms interlocking for 

 several plates above RR, ramule on about every Sth to 3rd brachial; rays strongly 

 angular. BB visible beyond column. Mus. Comp. Zool. 



16. Basal view of same, showing non-differentiation of BB. 



2a. Similar specimen, with rays interlocking above RR. 



2b. Basal view of same; BB visible as small points beyond the column. 



3. Basal view of large specimen, with regular iBr resting on shoulders of RR, and two of 



them touching BB. 



4, 5. Lateral view of two smaller specimens having iBr. 



6, 7. Basal views of smaller specimens with iBr ; showing BB larger and about equal all around, 

 and IBB within the column facet. 



8. Medium specimen similar to the type, with nearly complete stem, and no iBr. 



9. Young specimen with stem, having iBr, and unusually long intervals between ramules. 



10. Diagrammatic cross-section of base; showing IBB with slight flange extending a short dis- 



tance under BB, but not to edge of column facet. This is the greatest extension of 

 IBB found in the family Ichthyocrinidae. 



Lower Burlington limestone ; Lower Carboniferous. Burlington, Iowa. 



Figs. 11-16. Wachsmuthicrinus spinosulus (Miller and Gurley) 328 



Fig. no. The type; a very mature and well-marked specimen, much flattened. Has nodes and 

 transverse ridges strongly developed ; arms interlocking to above IIBr ; ramules about 

 every third Br. Large stem, covering BB and IBB. University of Chicago. 



Iii>. Outline restoration, showing normal contour of crown. 



12. Base of similar specimen, with spiniferous nodes on RR. BB entirely concealed by 

 column. 



130. Very young specimen, with relatively broad base and large RR; but basals nevertheless 

 hidden by column. 



13&. Opposite view, showing arms infolding at IIIBr. 



14. Mature flattened specimen from Lincoln County, Kentucky, with only obscure nodes. 



Note the interlocking of Br to above second bifurcation. 



15. Flattened specimen, with arms diverging on first brachial above axillaries ; large ramules 



at long intervals. 



16. Smaller specimen, showing tendency to similar divergence of rays. 



New Providence shales (Knobstone) ; Lower Carboniferous. Clark County, Indi- 

 ana; Bullit and Lincoln counties, Kentucky. 



All specimens figured on this plate, except the two types, are in the author's col- 

 lection. 



