110 AMERICAN JOURNAL 



Waldhetmia cranium, Mull. 



Terehratula cranium, Mull., Prod. Zool. Dan. p. 209. Rve., 

 Conch. Icon, pi iii, jfig. 6. Journ. de Conchy 1. 1861, p. 

 123. Jeffreys, Brit. Conch, ii, p. 11, v, p. 163. 



Terehratula vitrea, Flem. (non Born.) 



Terehratula subvitrea, Leach (teste Rve.) 



Terehratula glabra, Leach, Brit. Moll. p. 359, pi. xiv, fig. 3, 

 4, 5. _ 



Maeandrevia cranimn, King. 



Jlah. — Norway, McAndrew, Smithsonian Cab., 13,979. 



The foramen of this species is incomplete, and the area very 

 small. The loop is deeply reflected and of extreme tenuity. 

 The shells vary in their different stages of growth from lenticular 

 to ovate globose. 



Prof. King, whose perception of differences of structure is re- 

 markably keen, separated this species from Waldheirnia, under 

 the name of 3Iacandrevia, on account of the absence of the 

 septum and flat central lamina of the hinge plate, in the haemal 

 valve, and the want of the laminae which support the teeth, in 

 the neural valve of the typical species, as well as the incomplete 

 foramen. 



I have shown elsewhere in this paper that the foramen may 

 be complete or incomplete in the same species, that the dental 

 laminae of the neural valve may also be present or absent in the 

 same species (e. g. Laqueus suffusus), that the mesial septum 

 may be found in some species of a genus and not in others, that 

 in some species the dental laminae may be absent in the neural 

 valve while the central lamina of the hinge plate is still to be 

 found in the haemal valve (e. g. W. Raphaelis) and, therefore, I 

 cannot consider the structure in question as of even subgeneric 

 value.* 



Waldheimia Grayi, Dav. 



W. Grayi, Dav., Proc. Zool. Soc. 1852, p. 76, pi. xiv, fig. 1, 



2, 3. Rve., Conch. Iconica pi. ii, fig. 5, a, b, c. Journ. 



de Conchyl. 1861, p. 123. Cpr., Suppl. Rep. Br. Assoc. 



1863, p. 636. Cooper, Geogr. Cat. Moll. 1867, p. 3. 



Hah. Catalina Id., Coop. Corea, Belcher. Monterey, Dall. 



Smithsonian Cabinet, 401, Cp. ; 1651. 



This a good deal resembles Kraussina capensis externally. 

 The red bands of color in this fine species are sometimes ab- 

 sent. In such cases it is impossible to distinguish it from varie- 



*Mr. W. G. Binney (luv. Mass. 2d ed. p. 211), has placed this species 

 iu the family Rliynchonellidoe ! 1 



