14 SMITHSONIAN INSTITUTION 



PLATE IV 

 (All figures natural size except where otherwise stated) 



PAGE 



Figs. 1-22. Asaphocrinus omatus (Hall) 176 



Fig. la. One of the cotypes, original of Hall's fig. 2a, a mature flattened specimen; posterior view; 

 shows proportions of calyx and rays, and the suturally connected anal .v with incipient 

 ridge followed by narrow, tube-like plates, the latter with space for perisome at either 

 side. Collection Cornell University, Ithaca, N. Y. 

 lb. Outline restoration of same specimen, showing correct contour if undistorted. 



2. Another cotype, original of Hall's fig. 2b; anterior view. Am. Mus. Nat. Hist. 



3, 4. Posterior views of flattened specimens, to show condition of anal x with the longitudinal 



ridge, and succeeding plates; the first has a misleading appearance of radiating ridges 



upon the basal plates, due to accidental pressure of foreign objects, or to work of 



parasites. X 2. 

 5. Similar specimen showing a number of small plates in irregular order above anal. 

 6a. Very young specimen with arms short and immature (perhaps recuperated), preserving 



the surface ornament ; anterior view. X 2. 

 66. Detail of same enlarged, showing character of ornament on radial. X 4- 

 ya. Another young specimen, with surface ornament. X 2. 

 7b. Ornament of a IBr. X 4. 

 8,9, 10, II, 12. A series of specimens with arms folded, in various attitudes and sizes, all more 



or less flattened, and all showing the tube-like anal and following plates. 



13. Small undistorted specimen, showing contour of calyx, and proportions of alternating 



columnals. X 2. 



14, 15. Flattened specimens with arms more or less extended. 



16, 17. Specimens with arms separated from vertical pressure, showing rather wide iBr spaces ; 

 fig. 17 shows how the arms contract to very slender finials beyond the third bifur- 

 cation. 



18, 19. Specimens with stem almost complete ; also showing contraction of the arms beyond the 

 secundibrachs. 



20. Specimen but little flattened, with arms, stem, and branching root complete. 



21. Young specimen with stem nearly complete, showing elongated columnals characteristic 



of that stage. 



22. Type of Lecanocrinus nitidus Ringueberg, with arms completely extended to their hair-like 



finials, and lower part of stem with expanded, branching root. A minute specimen of 

 Homocrinus parvus, with arms complete, is lodged in the right ramus of the middle 

 ray. 



Rochester shales ; Silurian. Lockport, New York. 



Figs. 23-29. Asaphocrinus excavatus ( Ringueberg) 177 



Fig. 23. Ringueberg's type specimen, with arms, stem, and root complete, somewhat flattened. 



24, 25, 26. Specimens with calyx more turbinate, and with straighter sides than most of the 



preceding. 

 27,28,29. Specimens with wider interbrachial spaces, and remnants of perisome (poorly pre- 

 served at this locality), showing tendency toward the Tennessee form. Fig. 27, 

 r. ant. iR. X 2 ; fig. 28, r. post. iR ; fig. 29, r. ant. iR. 

 Rochester shales ; Silurian. Lockport, New York. 



Fig. 30. Asaphocrinus incisus (Ringueberg) 178 



Fig. 30. The type, with arms and large part of stem attached ; antero-lateral interradial view. A 

 single IBr in two rays. 



Rochester shales ; Silurian. Lockport, New York. 



All the specimens figured on this plate are from Lockport, New York, and all except 

 Hall's types, figs, i and 2, are in the author's collection. 



