200 Art. 1— M. Yokoyama : 



Family Rhynchonellidae. 



Genus KHYX€IIO\'EIXA, Fischer. 



333. Rhyiichonella psittacea, (Chemnitz) 

 var. tvoofltvardi, (Adams). 



P]. XVn. Fig. 13. 



Rhynchonella psittacea var. roooditardi. Davidson, Mouogr. Rec. Brach., p. 168, pi. 



XXIV, figs. 12. 13. Pilsbry, Cat., p. 153. 

 Rhynchonella woodwanli, Adams, Ann. Mag. Nat. Hist., 3d Ser., vol. XI, p. 100. 



One perfect specimen and a few isolated valves. 



The shell is somewhat triangular in outline, glohose, hroadest 

 in the middle and laterally- rounded. From the t\'pical form of R. 

 psittacea it is distinguished by the absence of radiating lines, the 

 smaller and less curved beaks and the rounded ventral margin 

 produced in the middle. The perfect specimen measures 22.3 

 millim. in height, 22 millim. .in breadth and 16.5 miUim. in thick- 

 ness. It is therefore somewhat larger than tliat figured by David- 

 son in his monograph. 



Fossil occurrence — Shito. 



Living. — Northern and Western Japan. 



