PLATE XX. 



Astroceinus tetragonus, T. 6f T. Austin, sp., p. 300. 



Page 

 Fig. 1. Inferior asjiect of a specimen in which the small basal plate has been removed ; 



the abortive radial is just seen below, and the irregular interradius above. Car- 

 boniferous Limestone, Yoi-kshire. x 6 26 



Fig. 2. A radial view of the same specimen, with one ambulacrum, and two radio-deltoid 



sutures visible. x 6 26 



Astrocrinus Benniei, Eth. Jn., sp., p. 301. 

 Carboniferous Limestone, Haddingtonshire, Peeblesshire, &c. 



Fig. 3. Exterior view of a radial plate, showing the sinus and lip. x 10 26 



Fig. 4. Interior of the same plate, with traces of the hydrospires, Fig. 3. x 10. . . . 96 



Fig. 5. A deltoid plate as seen from above, accompanied by an enlargement of one of its 

 tubercles seen from the side, with the apex of the same, on which is visible the 



perforation for the attachment of a spine. x 10 302 



Fig. 6. Side view of a long interradial process. x 10 301 



Fig. 7. Summit view of a specimen in which the ambulacra are more or less preserved. 



x 12 299 



Fig. 8. Under view of an example ornamented with acute prickly tubercles. x 12 . . 296 



Fig. 9. Summit view of a small specimen, with the irregular interradius much produced, 



and the ambulacra removed. x 10 302 



Fig. 10. Under view of the same individual. x 10 300 



Fig. 11. Summit view of a similar example, but with the four normal ambulacra preserved. 



x 10 299 



Fig. 12. Interradial view of the same specimen, with two ambulacra in situ, and an inter- 

 radial and a radio-deltoid suture visible ; an enlarged tubercle and spine are 



also shown. x 10 302 



Fig. 13. Under view of the same specimen, exhibiting the irregularity of the basal plates. 



xlO 299 



Fig. 14. Summit view of a distorted specimen, seen rather obliquely. x 8 .... 302 



Fig. 15. The azygos radius, showing the two irregular basals below, and the modified radial 



resting on them. x 8 26 



Fig. 16. View of a little-crushed individual, with the irregular interradius forwards, and the 



radio-deltoid sutures well shown. x 8 302 



Fig. 17. Exterior of one of the incomplete radial plates, which are next to the azygos radial. 



xlO 26 



Fig. 18. Interior of the same plate, with traces of two imbedded hydrospires. x 10. . 96 



Fig. 19. Exterior of the azygos radial, with its notch-like sinus. x 10 26 



Fig. 20. Interior of the same plate, with traces of imbedded hydrospires. Coll. Geol. 



Survey, Scotland. x 10 96 



