136 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.41. 



Antedon depressa d'Orbigny. 



Fig. 7. Basal view of specimen from which the centro-dorsal has been removed; 

 approximately X 2. After de Loriol, 1884-1889. (PI. 221, fig. la.) 

 8. Lateral view of cup to which the centro-dorsal is attached; X 3. After De 

 Loriol, 1884-1889. (PI. 221, fig. 26.) 



Plate 9. 



Uintacrinus sodalis Grinnell. 



Fig. 1. Normal base of "Form D" with unusually large centrale. After Springer, 

 1901. (PI. 2, fig. 10.) 



2. Normal base of "Form D" with smaller centrale. After Springer, 1901. 



(PL 2, fig. 12.) 



3. Base of "Form D " in which the centrale meets the basals as well as the infra- 



basals, and is decagonal in outline. The infrabasals are comparatively 

 minute, but of equal size. After Springer, 1901. (PL 2, fig. 9.) 



4. Base of "Form D" in which the centrale meets three of the basals. Two of 



the infrabasals are much smaller than the other three. After Springer, 1901. 

 (PL 2, fig. 18.) 



5. A varient of the foregoing in which the centrale has fused with one of the small 



infrabasals. After Springer, 1901. (PL 2, fig. 7.) 



6. A base in which fusion has been carried still further. The centrale has here 



fused with two of the infrabasals. After Springer, 1901. (PI. 2, fig. 6.) 



7. A base in which in addition to the centrale becoming fused with two of the 



infrabasals, fusion has taken place between two of the other infrabasals. 

 After Springer, 1901. (PL 2, fig. 5.) 



8. Base in which fusion has taken place probably between the centrale and two 



of the infrabasals on the one hand, and between the three remaining infra- 

 basals on the other. After Springer, 1901. (PL 2, fig. 4.) 



9. A base of "Form M" in which fusion has been effected between two of the 



basals. After Springer, 1901. (PL 2, fig. 14.) 



10. Base of ' ' Form M " showing centrale of nearly minimum size. After Springer, 



1901. (PL 2, fig. 2.) 



11. Base of "Form M " showing centrale of maximum size. After Springer, 1901, 



(PI. 2, fig. 1.) 



Megistocrinus rugosus Lyon and Casseday. 



12. View of fused basals, surrounded by the radials and proximal anal. It is to be 



noted that the fused basals form a regular pentagon with straight faces. 

 After Wachsmuth and Springer, 1897. (PL 48, fig. 6a.) 



Plate 10. 



Saccocoma tenella Goldfuss. 



Fig. 1. Specimen showing cup and structure of arms. R=radial; c=centrale; X7. 

 From Bather, 1900. (Text fig. 68, 1, p. 155.) After Jaekel. 



Saccocoma pectinata Goldfuss. 



2. Complete individual to show coiling of the distal portions of the arms; Xi- 



From Bather, 1900. (Text fig. 68, 2, p. 155.) 



3. Lateral view of cup and proximal arm ossicles; X2^. R=radial. From 



Bather, 1900. (Text fig. 68, 3, p. 156.) After ZitteL 



