300 



PALEONTOLOGY OF NEW YORK. 



Fio. 2S3. Btechtria [Btmiptycliina) tublatU, Waagen. 

 Dorsal view; 8howinK the smooth exterior. 



(Waagrk.) 



single form) of smooth species without dental plates. It is here proposed to 



separate these shells from Hemiptt- 



CHiNA and to distinguish them by 



the term Beecheria,* giving a brief 



account of the interior structure as 



exemplified in B. Davidsmi, sp. nov.,f 



of the Carboniferous limestone of 



Windsor, Nova Scotia. 



The general character of the interior is that of Dielasma, except that the 

 dental plates are wholly absent or represented only by faint ridges which 

 never reach the bottom of the pedicle- 

 valve. The peculiar myiferous hinge- 

 plate of Dielasma is wholly merged 

 with the valve, but the crural ridges 

 are still retained and the descending 

 lamellaB originate from them at the 

 bottom of the valve in very much the 

 same way as in Dielasma. The crural apophyses are broad and erect, there 

 being no part of the descending branches behind them. Sometimes the 

 brachial valve retains a low muscular impression which has the form of 

 the platform of Dielasma. This species and Beecheria {Hemiptychina) sublavis, 

 Waagen, constitute the known representatives of this type of structural 

 variation. 



no. 2-24. Beecheria DatidtoiU, sp. nov. 

 An enlarxc'l proOle ol' the brachidium; showing the man- 

 ner in which lamellae arise [rota the bottom of the raire, 

 the broad posterior JURal processes and the much nar- 

 rower descending lamcllie. The anterior transverse or 

 reflected band is not fully retained. (c ) 



Gencs CRYPTACANTHIA, White and St. John. 1867. 



1867. Waldheitniaf (Cryptacanthia), White and St. John. Trans. Chicago Academy of Sciences, 

 vol. i, pt. i, p. 119, fig. 3. 



Our knowledge of this genus is still very imperfect. The authors described 

 as Waldhdntia? compada, a rather small, plano-convex or naviculoid shell from 



* In recognition of his important contributions to our knowledge of the Brachiopoda. 

 t This is the shell identified by Davidson as Terebratulu sacctdus, Martin. (On the Lower Carboniferous 

 Brachiopoda of Nova Scotia; Quart. Journ. Geol. Soc., vol. xix, p. 169, pi. ix, figs. 1-3, 1863.) 



