292 PALEONTOLOGY OF NEW YORK. 



contour of the shell, highly developed median septum, with the fimbriated 

 descending branches of the brachidium, warrants the separation of this type 



Fig. 211. Fig. 212. 



Centronella (Barttina) Anna, Hall. 

 Dorsal aut-l pioiile. views ol" a prepaiatioii of the bracliiiliuiii; bhowing the binge-plate, broaii jugal procesijea, lim- 

 briated descending lamellae, long recurved lanielloe, and prominent median septum in the brachial valve. 



(0.) 



of structure from other known genera, from which it may be distinguished by 

 the term Harttina. 



A Carboniferous species, Waldheimia Coutinhoana, with an essentially similar 

 internal structure, has been described by Derby * from the Amazonas. This 

 shell is rather more biconvex than Harttina Anna, and has a lesser develop- 

 ment of the dorsal septum ; together, they represent the continuance of the 

 CRYPTONELLA-type of brachidium into the later palaeozoic faunas. 



* Bulletin iif the Cornell University, vol. i, No. 2, p. 3, pi. iii, tig. 22; pi. viii, fig. 6; pi. ix, tigs. 1, 

 2. 1874. 



