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 



FlO. 211. Pio. 214. 



CentrontUa (Bartlina) Anna, Hall. 

 Oorul and profllo.views or a proparalion of Uic brachiUium; showing the hinge-plate. Ifi-oad jugal processes, flm- 

 briated descending lamellae, long recurved lamella, and prominent median septum in the brachial Talre. 



(C.) 



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 Derbt * 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 of the Cornell University, vol. i, No. 2, p. 3, pi. iii, fig. 22 ; pi. viii, fig. 6 ; pi. ix, figs. 1, 

 2. 1874. 



