10 . SMITHSONIAN INSTITUTION 



PLATE II 



(All figures natural size except where otherwise stated) 



^ ^ ' PAGE 



Figs. 1-15. Lecanocrinus billingsi Angelin 132 



Fig. I. Probably the original from which Angelin's pi. 22, fig. 25, was composed, a much flattened 

 specimen with arms complete; posterior view, showing the small RA. X 2. 



Snackgardet, Wisby (d). 

 2a, h. Left anterior and posterior views of smaller specimen, flattened and injured. X 2. 



3. Ventral view of another specimen at distal margin of RR. Shows great thickness of 



plates; fossae on radial facet; and IBB from interior with trilobate rim around the 

 lumen. X 3- 



4. Calyx of another specimen showing a faint wrinkled sculpture. X 3- 



5. 6. High form, and 7, low form, of calyx. X 2. 



8-15. A series of specimens showing irreguarity in position of radianal and anal plates : 



8. RA very small and triangular. X 2. 



9. RA in primitive position in form of R. under r. post. ray. X 2. 

 lb. RA located vertically below anal x. X 2. 



11. No RA; post. B large. X 2 (s other specimens are in this condition). 



12. No RA ; r. post. B large. X 2. 



13. No anal x, but RA is normal. X 2. 



14. No anal x; RA in primitive position in form of R. X.2. 



150, &. Malformed specimen, with normal RA and anal x, but only 3 RR (marked I, II, III). 

 In the ring of BB are 7 plates (marked 1-7) of varying size and form, and a quad- 

 rangular plate (-)-) is seen on the right side between the rings of BB and RR. Out- 

 line sketch not exactly drawn to scale. X about S. 



(Out of 134 specimens in the Riks Museum 15 — or over 11 per cent — are abnor- 

 mally developed, showing a tendency to instability of characters much greater 

 than in the preceding Tennessee species.) 

 Wenlock Gr. ; Silurian. Gotland, Sweden. 



All specimens are from Wisby, horizon (d), and in the Riks Museum, Stockholm, 

 unless otherwise stated. 



Figs. 16-21. Lecanocrinus fascietatus (Angelin) 133 



^ Fig. 16. Specimen of the usual form; posterior view. X 2. Nafdem*(c). 



170, &. Specimen of higher form; 1. ant. and post, views. X 2. Nafdem (c). 



18. Specimen from Nafdem (c) with anal x not so much truncate as usual. X 2. 

 iga,h,c. Small specimen from Hablingbo (c) with high RR and plates thicker than usual; 



1. ant., post., and distal views. X 2. 

 igd. Granular surface ornament of same, near upper edge of a radial. X 12. 

 200, h, c. Anterior, posterior, and distal views of large specimen from Nas (d), the last show- 

 ing thinness of calyx plates. X 2. 

 ■ 2la,b,c. Fragments of arm-ossicles from Wisby (c) ; a exterior, X2; &, IBr, from proximal 

 face, X 2; c, granular surface, X 12. 



Wenlock Gr. ; Silurian. Gotland, Sweden. 

 All specimens in the Riks Museum, Stockholm. 



Figs. 22, 23. Lecanocrinus lindstromi n. sp 134 



220, b, c. The type specimen. Anterior, posterior, and right posterior views of perfect crown. 



X2- Hoberg (d). 



22d, e. Basal and distal views of same. X 2. 



23(1!. h, c, d. Various views of another specimen with a lower cup, from same locality ; d shows 

 the pentagonal periphery of cup at top of radials. X 2. 



Wenlock Gr. ; Silurian. Gotland, Sweden. 

 All specimens in the Riks Museum, Stockholm. 



