PLATE XIII. 



CODASTER TRILOBATUS, McCoy, p. 268. 



Page 

 Fig. 1. Summit view of a very perfect specimen, showing the ambulacra, interradial ridges, 



radio-deltoid sutures, mouth, anus, and seven hydrospire slits on each side of 



an ambulacrum. Carboniferous Limestone, Lancashire and Yorkshire. x 3. 22 



Fig. 2. Inferior aspect of the same specimen, showing the basal plates and the trilobate 



cup. x 2 16 



Fig. 3. Interradial view of the same, showing the basal cup and radial plates. x 2 . . 24 



Fig. 4. Summit view of another specimen, in which there are only four hydrospire-slits 



visible on each side of an ambulacrum. x 4 13 



Fig. 5. Vertical section of a portion of a calyx, with the free ends of the hydrospires pen- 

 dent within the visceral caviuy. x 2 88 



Fig. 6. A naturally weathered calyx, in which a radial plate has been removed, exposing 



seven hydrospires on each side of the ambulacrum. x 2 88 



Fig. 7. Portion of a cross section of the calyx shown in Fig. 5, seen from above, with the 



eight groups of hydrospires. x 2 88 



Fig. 8. Portion of a summit, seen obliquely, with two radio-deltoid sutures, and ten hydro- 

 spire-slits on each side of the ambulacrum. x3 8 



CODASTER TRILOBATUS, VOT. ACUTUS, McCoy, vai\, p. 269. 



Fig. 9. Interradial view of the upper portion of a calyx. Carboniferous Limestone, 



Lancashire and Yorkshire. x 4 23 



Fig. 10. Radial view of a complete calyx. x 3 16 



Fig. 11. Interradial view of the upper part of a calyx of a more robust form. X 4 . . 23 



Fig. 12. Radial view of a complete calyx. x 3 24 



Fig. 13. Under view, showing the basal plates and the tripod cup. x 3 16 



Fig. 14. An ambulacrum, showing the lancet-plate and three side plates in situ on each 



side. x 8 55 



Fig. 15. Radial view of a large variety, with a more pointed base, and some remains of 



ornament on the plates. x 3 16 



Orophocrinus verus, Cumb. sp., p. 290. 

 Fig. 16. Part of an ambulacrum, showing the large sockets between the side plates. Car- 

 boniferous Limestone, Lancashire. x 12 61 



Acentrotremites ellipticits, Cumb., sp., p. 235. 



Fig. 17. Basal view, with the columnar cavity occupied by the remains of a stem-joint. 



Carboniferous Limestone, Somersetshire. Natural size 12 



Fig. 18. Interradial view, showing the broad ambulacra, and the position of the spiracles on 



the radio-deltoid sutures. Natural size 108 



Fig. 19. View of an ambulacrum, with most of the side plates in position, and below them 



the lancet-plate broken short-off; the spiracles and the anus are also visible. 



xlJj 93 



Cryptoschisma Schuxzi, d'Archiac &<; de Vern., sp., p. 281. 

 Fig. 20. A portion of the summit, showing two spiracles in each interradius, with the narrow 

 exposed portions of the deltoid plates between them. Lower Devonian, Asturias. 

 x6 97 



