32 MEMOIRS OF THE STATE MUSEUM 



objects by the substance of the shell, and afterward broken away from 

 its attachment. (See Davidson, General Summary, pp. 355, 356.) It 

 is true that the anterior edge of this area may be rough and uneven, 

 but the lateral edges appear invariably straight and diverge at an essen- 

 tially constant angle. The latter represent the lines of attachment of 

 the internal plate to the interior of the valve, and if the shell has been 

 broken in detachment from foreign bodies, the fracture in these direc- 

 tions has been guided by these lines, but on the unsupported anterior 

 margin it has been rough and irregular. Upon the hinge-line of the 

 ventral valve, there exists no aperture for the protrusion of the pedicle ; by 

 the peculiar development of the articulating processes of both valves, the 

 entire cardinal margin is closed, and therefore the passage between the 

 internal plate and the surface of the valve may have been for the use of 

 this organ ; or, it may be suggested, that as this space is rather too 

 narrow and explanate for such a purpose, Eichwaldia may have been 

 attached by the substance of the shell, the internal shelf acting as a 

 support to the strain upon the umbo, and a protection to the animal in 

 case the shell were broken from its attachment. 



Anastrophia internascens, Hall, 1879 



Plate III, Figs. 14-16 



, Hall. Twenty-eighth Ann. Rept. N. Y. State Mus. Nat. Hist., p. 168, pi. 26, figs. 41- 



49. 1879. 

 , Hall. Eleventh Ann. Rept. State Geol. Indiana, p. 311, pi. 26, figs. 41-49. 1882. 



In tracing the development of this species, the principal feature to 

 be noticed is that the elemental shell conforms with the type of an ordi- 

 nary brachiopod, such as Rhynchonella, that is, the dorsal valve, although 

 somewhat the more convex, is smaller than the opposite valve, while 

 in the mature state the dorsal valve is considerably larger and pro- 

 jects beyond the beak of the ventral valve. It is the development of this 



