300 
PALEONTOLOGY OF NEW YORK. 
single form) of smooth species without dental plates. It is here proposed to 
separate these shells from Hemipty- 
CHiNA and to distinguish them by 
the term Beecheria,* giving a brief 
account of the interior structure as 
exemplified in B. Davidsoni, 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 
° Fig. 224. Beecheria Davidsoni, sp. nov. 
are still retained and the descending An enlargeflpronie or the bracliHlium; showing the man- 
. . ner in which lamellre arise IVom the bottom of the valve, 
lamellsB originate from them at the the broad posterior Jugal processes and the much nar- 
. rower descending lamellsB. The anterior transverse or 
bottom of the valve in very much the reflected band is not rully retained. (c) 
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) suhlczvis, 
Waagen, constitute the known representatives of this type of structural 
variation. 
Fig. 223. Beecheria (Hemiptychina) sublcevis, Waagen. 
Dorsal view; showing the smooth exterior. 
(Waagen.) 
Genus CIIYPTACANTHIA, White and St.John. 1867. 
1867. Waldheimia? (Cryptacanthia), White and St. John. Trans. Chicago Academy of Sciences, 
vol. i, pt. i, XI. 119. 3. 
Our knowledge of this genus is still very imperfect. The authors described 
as Waldheimia? compacta, a rather small, plano-convex or naviculoid shell from 
* In recognition of his important conti'ilnitions to our knowledge of the Brachioiioda. 
t This is the shell identified by Davidson as Terebratula saccuhos, Martin. (On the Lower Carboniferous 
Brachiopoda of Nova Scotia; Quart. Journ. Geol. Soc., vol. xix, xi. 169, pi. ix, figs. 1-3, 1863.) 
