PLATE VI. 



IIetekorlastus Cumbeklanim, E. &; C, p. 257. 



Page 

 Fig. 1. Radial view of an entire specimen, with the civet deltoid processes. Carboniferous 



Limestone, Northumberland. Coll. P. II. Carpenter. x4 11 



Pig. 2. Summit view of the same specimen. x I II 



Pig. .'5. lnterradial view of the same, on a larger scale, showing a spiracle at the base of 



one of the deltoid processes. x6 107 



Fig. 1. Inner aspect of a deltoid process, showing the grooves which terminate in the two 



spiracles. x6 107 



Fig. 5. The single anal spiracle, excavated in the anal deltoid. x 6 250 



Fig. 6. External aspect of a radial plate. x 6 257 



Mesoblastus angulatus, G. B. Sby., sp., p. 185. 



Fig. 7. Summit view, exhibiting the double spiracles. Carboniferous Limestone, Lanca- 

 shire. x2 101 



Mesoblastus crenulatus, Roemer, sp., p. 183. 



Fig. 8. Summit view, showing the spiracles at the sides of the deltoid plates, and the deep 



marginal pitting round the mouth upon the proximal ends of the latter. 



Carboniferous Limestone, Belgium. x 3 58 



Fig. 9. Inferior aspect of another specimen, exhibiting the protuberant base, and ridged 



basal plates. x 3 15 



Fig. 10. Portion of an ambulacrum, with the lancet-plate and hydrospire-plates exposed. 



x8 49 



Mesoblastus elongatus, G. B. Sby., sp., p. 186. 

 Fig. 11. Portion of a worn ambulacrum. Carboniferous Limestone, Lancashire. x8 . (il 



Mesoblastus Sowerbii, E. §■ C, p. 187. 

 Fig. 12. Radial view of a specimen showing the wide ambulacra, moderately large deltoids, 



and the protuberant base. Carboniferous Limestone, Lancashire. x 2 . . 15 



Fig. 13. Summit view of the same, with the double spiracles encroaching considerably on 



the deltoid plates. x 2 104 



Fig. 14. Inferior aspect of the same, showing the protuberant base. x2 17 



SCHIZOBLASTUS MELOXOIDES, M. (5f W., Sp., p. 22G. 



Fig. 15. lnterradial view, showing the deltoid plates and the obtuse iuterradial ridges. 



Subearboniferous, Iowa. Coll. Wachsmuth. x 2 : . . 227 



Fig. 10. Summit view of the same specimen, showing the spiracles and the same features as 



in Fig. 15. x 2 Ill 



Schizoblastus Rofei, E. t$ C, p. 228. 

 Fig. 17. Inferior aspect, showing the slightly concave base. Carboniferous Limestone. 



x3 15 



