598 



Forty-fifth Report on the State Museum. 



ridge which bifurcates anteriorly inclosing a cavity for the inser- 

 tion of the anterior adductors. (Type, D. Dutertrii, Murchison 

 (sp.). Devonian.) 



Cadomella, Munier-Chalmas. 1887. 



Shell nearly flat or gently concavo-convex ; hinge-line long, 

 straight ; beak of pedicle- valve scarcely prominent ; cardinal areas 

 linear ; deltidium narrow. On the interior the pedicle- valve bears 

 divergent teeth between which lies an apophysis, serving as a 

 base of attachment for the accessory diductors. The principal 

 diductor scars are flabellate, but do not extend beyond the 

 umbonal region. In the brachial valve is a stout cardinal pro- 

 cess, grooved upon its upper surface near the lateral margins. 

 Socket- walls greatly elevated and continued into curved crural 

 apophyses which have a tendency to become free toward their 



&T&S-- 



Cadomella Moorii. 

 Fig. 271.— Interior of pedicle- valve. Fig. 272.— Tnterior of brachial valve. 



Chalmas.) 



(MlTNIER- 



extremities. There is a median septum which, at its anterior 

 end, at the center of the valve, is strongly elevated and bilobed. 

 The four adductor impressions united into two cordate scars 

 whose outer margins are strongly thickened. 

 Type, Cadomella Moorii, Davidson (Lias). 



Strophonella, Hall. 1879. 

 (Plate 15, Figs. 5-11.) 



Shells semicircular or semielliptical, concavo-convex, resupi] 

 nate, the pedicle valve concave and the brachial valve convex. 

 Area of pedicle-valve striated, solid, with or without a centra- 

 deltidial scar', or rarely a partial foramen, with similar features 

 on the narrow area of the brachial valve; inner margins 

 of the cardinal areas of each valve orenulate, and from beneath 



150 



