222 
SMITHSONIAN INSTITUTION 
PLATE 25 
(All figures twice natural size unless otherwise stated) page 
(Foreign species introduced for comparison) 
Pisocrinus pilula DeKoninck 8o 
Fig. I. Complete crown with stem, showing the extremely long arms. After Bather. Gotland. 
2, 2a, 2b. Conical specimen from Gotland ; radianal, basal and ventral views. 
3&- A maximum high specimen from Dudley, England; ant., basal and ventral views. 
4, 4a, 4b. A smaller, more globose specimen from Dudley; 1 . ant., 1 . post, and ventral views; 
processes tending to lance-head form. 
5 , 5 u, Sh. A more depressed form from Dudley; r. post., basal and ventral views. 
6, A typical form with almost complete stem ; first brachials in place enclosing the orals ; 
ant. view. Dudley. 
6a. Ventral view of same showing the 5 orals, slightly fractured at the center. X 8. 
6.t'. Ventral view of an average specimen from Gotland. After Bather. 
Wenlockian, Silurian ; Gotland and England. 
Pisocrinus ollula Angelin 8o 
Fig. /. L. ant. view of specimen from Gotland. .After Bather. 
8. Specimen from Gotland, showing BB limited to column facet. After Bather. 
g. Ventral view of specimen showing wide facets, and processes widening inward. Gotland. 
After Bather from Angelin. 
10. Basal view of another specimen from Gotland, with extremely small BB at bottom of 
deep cavity and tendency to pentagonal outline ; for comparison ivith P. quinquelobus. 
Pisocrinus pocillum Angelin 8o 
Figs. II, iia. The type, from Gotland, post, and 1 . ant. views. After Bather from Angelin. 
Pisocrinus sp 8o 
Figs. 12, 12a. Abnormal specimen from Dudley, with processes bordered by a raised rim, and of a 
very different shape from those of other forms ; lateral and ventral views. 
Pisocrinus sp 8o 
Figs. 13. 13a. A very small specimen from Gotland, having the form and structure of P. gem- 
miformis. 
13^, I3<^. Details of radial facets and processes of same. X 8 . 
14. A larger specimen of similar form from Dudley, England. 
All from the Wenlockian formation, Silurian. 
All the specimens except those of figs, i, 7, 8, 9 , ii, are in the author’s collection, 
U. S. National Museum. 
e Triacrinus altus (Muller) 74 
Figs. 15, 15a, i5h. Characteristic specimen from the Middle Devonian, Eifel, Germany; r. post., 
dorsal and ventral views. Note the 3 BB, and facets and processes like P. tennes- 
scensis. 
Triacrinus depressus (Muller) 74 
Figs. 16, 1 6a, i6b. L. ant. dorsal and ventral views of a typical specimen with 3 BB. Note the 
wholly different form of processes. 
17, 17a, 17b. Ant., dorsal and ventral views of specimen with 4 BB. 
18, i8a, J8b. Similar views of specimen with 5 BB. 
Middle Devonian; Eifel, Germany. 
