BRACHIOPODA. 313 



Genus CHONETELLA, Waagen. 1884. 



1884. Chondella, Waage.v. Mem. (ieol. Survey of India ; Palaioiitolojfia Imiica, yurie.s xiii, vol. i, 



No. 4, J). 0,57, jil. Ixxxi, tigs. 3-8. 



Diagnosis. Shell small, normally concavo-convex. Surface rounded, witli 

 radial striiE ; cardinal area narrow ; deltidiura, cardinal .spines and teetli as in 

 Chonetes. In the pedicle-valve the adductor impressions are elongate, and are 

 partially enclosed by the larger cardinals. The brachial valve has a small 

 trilobed cardinal process, which is continued into a low median septum. The 

 muscular area is quadrijjartite and very distinct. The 

 brachial ridges are sharply defined and appear to origi- 

 nate near the outer extremities of the posterior adduc- \1 

 tors, making a broad outward, and a more abrupt inward 

 curve completing one volution. Surface in the pallial 

 region strongly papillose. ,, „^ ,., , „ 



Type,ChoneteUa reaiwto, Waagen. Upper Carboniferous. xncvwwr.Eti. 



Observations. Dr. Waagen has proposed this division for a single species 

 from the Productus limestone of India. Aside from the broadly curved brachial 

 ridges, its characters are so strongly chonetoid as to render its separation from 

 Chonetes exceedingly difficult.* The author surmises that some small shells 

 figured by Davidsonj and regarded by liim as varieties of Productus longispinus, 

 from the Carboniferous shales of Lanarkshire, Scotland, belong to the same 

 group. 



*The trilohed cardinal process is de.serilied in its anterior aspect onlj', and it is quite pi'obable that upon 

 Us posterior face it would be found more similar to that of Chonetes. The ci-ural plates are very obscure, 

 making the process appear free and erect ; but this is also true of some species of Chonetes, e.g., Chcmetes 

 coronata, Conrad. 



t Carboniferous Brachiopoda, pi. xxxv, figs. 18. 19. 



