142 AMERICAN JOURNAL 



Rve., Conch. Icon. pi. viii, fig. 33 ; Journ. de Conchyl. 

 1861, p. 130. H. and A. Adams, Gen. Rec. Moll. p. 

 577, pi. 131, figs. 2, 2a. Chenu, Man. de Conchyl. ii, p. 

 208, figs. 1061—1063. 



? Bouchardia fibula, Rve., Conch. Icon, vii, fig. 30 a, b. 



JIab. Rio Janeiro, 13 fathoms, McGillivray. 



This very remarkable shell is well distinguished from the last 

 genus in the form of the neural umbo, the cardinal process and 

 hinge-plate, and the apophyses, which principally differ from 

 Kraussina in being posteriorly instead of anteriorly directed. 

 The figure given by Woodward and Gray gives a poor idea of it. 

 A much better one may be found in Davidson's introduction to 

 the classification of the Brachiopoda, plate vi. The area where 

 the deltidium should be is flat or excavated. 



The other species, referred by Reeve to this genus, does 

 not belong to it. 



The genus is only known in a recent state. 



Section PLATIDIIN^. 



Shell with the loop attached, not reflected ; animal with sig- 

 moid brachia meeting behind the mouth, without any spiral me- 

 dian lobe or lateral loops. Cardinal process absent. 



Genus PLATIDIA, Costa. 



Platidia, 0. G. Costa, Fauno del Reg. Napoli, Jan. 1852, p. 



47. 

 Morrisia, Dav., An. Nat. Hist. May, 1852, p. 371. Woodw., 



Rec. and Foss. Shells, p. 218. Rve., Conch. Icon, pi. 



X ; Journ. de Conchyl, 1861, p. 134. Dav., An. Nat. 



1861, p. 39. Bronn, Malac. iii, pt. i, pp. 304, 806, 309. 



Chenu, Man, de Conchyl. p. 208. H. and A. Adams, 



Gen. Rec. Moll, ii, p. 579. 



Shell with a large foramen encroaching upon both valves, 

 ventral valve with a small straight area, deltidia absent or rudi- 

 mentary, valves articulated by teeth and sockets, structure 

 coarsely punctate. Apophysary system reduced to two short 

 arms provided with crura, proceeding from the hinge margin and 

 attached to a small central septum. 



In the last section the haemal processes were absent and the 

 neural portion of the loop, in a modified form, present. In this 

 section the reverse is the case. 



