52 SMITHSONIAN INSTITUTION 



PLATE XXIII 

 (All figures natural size except where otherwise stated) 



PAGE 



Figs. 1-8, 10. Forbesiocrinus nobilis De K. and Le H. (continued) 24Q 



(Also on Plates XXI, XXII and XXIV) 



Fig. la. A large, somewhat flattened specimen, in excellent preservation ; from right posterior 

 radius. It shows the surface ornament; the curved and corrugated distal margin of 

 iBr plates continuous with the upper lateral face of IBrj and following brachials ; the 

 plates of the anal interradius,. some to the right slightly disturbed, and perhaps the 

 base of a tube-like series tending to the right. The distal brachial divisions in the 

 right ramus of r. post, ray are irregular, indicating injury and reparation. 



lb. Anterior view of calyx of same, to IBri. 



If. Right anterior ray of same, detached above IBr,, ventral view. Shows the corrugated 

 lateral face of the brachials from IBrz — on which deep fossae are seen at the lower 

 angular face — to IIIBrs, where it has thinned and about disappeared ; also the broad, 

 shallow ventral concavity of the lower brachials, gradually passing into a median 

 depression flanked by more or less parallel grooves connecting irregularly with the 

 rugae of the margin. At the left an illBr is in place, with similar corrugated 

 distal margin. X 2. 



id. Left lateral view of same (being the same edge exposed in fig. la) ; showing the structure 

 of the lateral face of brachials more plainly. X 2. 



le. Distal portion of an arm, showing the great proportionate depth of the higher brachials. 



2. Another large, much flattened specimen, seen from right posterior radius. It shows the 



same parts as fig. i, with addition of proximal portion of stem, but the arm divisions 

 are here normal. The plates seen beyond the second range in the right posterior 

 interradius are not interbrachials, but are displaced brachials from some of the 

 broken rays partly exposed in the matrix. 



3. Stem of another specimen with IBB and two BB attached ; showing sutural fossae at distal 



margin of post. B. 



4. Diagram of base, composed from figs, i and 3; showing IBB, and axial opening in stem. 



5. Diagram showing plates of anal side, from figs, i and 2; anal and following plates 



shaded in diagonal lines. 



6. An axillary IBr, showing surface markings. X 2. 



7. Ventral view of similar plate ; showing lateral margins corrugated for attachment of 



perisome. X 2. 



8. Similar view of another plate with sutural fossae part way up ; showing that solid inter- 



brachials sometimes extended higher up than is indicated in the two principal speci- 

 mens, figs. I and 2. 



9. A plate with margins entirely occupied by fossae, showing connection of solid iBr some- 



times as high as the top of the axillary IBr. This specimen, of a species not de- 

 scribed, is from Fern Glen, Missouri. 



10. Proximal face of a radial. X 2 (enlargement fraction omitted on plate). 



Lower Carboniferous, Tournai Stage. Tournai, Belgium (except fig. 9). 



Figs. 11-13. Forbesiocrinus sp 248 



Fig. Iia. Part of a ray reconstructed from isolated R and IBr plates, dorsal view ; showing angular 



sutural faces on R and IBri and 2, for connection with solid interbrachials; and 



straight face of I Bra. 



11&. Lateral margin of same; showing sutural faces with large fossae on R and IBri and 2, 



and corrugated faces for attachment of perisome on upper half of IBr2, and on IBra. 



12. Distal face of a radial. X 2. 



13. Proximal face of first primibrach. X 2. 



New Providence beds (Knobstone) ; Lower Carboniferous. Button Mould Knob, 

 Kentucky, and Clark County, Indiana. 



All specimens figured on this plate are in the author's collection. 



