<>) oni 



it reads I should say that he refer- to a ./;i/.ilii i or 



rsimilix and not to a \<inn>fmia which the shell here inuli" ieration 



Undoubted!} tl The latter dillers iii :it lei 



Cbaneten brought out in Hall ption. and cither one would in my opinio 



suHicient to defeat specific identity. Thus. he says the Leak- arc "situated al.out 

 fourth tlie length of the -hell from the anterior end." whereas in Whitlield'- 

 ; they are much nearer the anterior extremity: then he gives the impression 

 that the anterior, [inferior and hasal margins are almost uniformly rounded, while 

 in the present -pene-. the outline is alway- more or less quadrangular. I'nder the 

 circum-tatices 1 might have Keen ju.-titied in proposing a new name, but as the 

 questions involved would .still lie open (a study of the original of Hull's description 

 alone can an.-wer them), if -eemed best to refer to the species provisionally as 

 abo 



"in nioln \\'hitfield ('llalh .-losely related to I'. li<n/ni>ina Satlord 



I Iricli. l-'rom tlietir-t it is di-t in^iii-hed I >y its greater convexity 

 and length, more anterior and larger Leak-, and almost rectangular instead of 

 rounded anterior side. The ca-t figured on plate xxxvin preserves the impressions 

 of the hin^re teeth. The cardinal teeth were rather -mall, nlili.jue. and numbered 

 four in each valve. The posterior teeth were slender, nearly horizontal, and three 

 in nu in her. In V. gibbosa the anterior margin forms a wider angle with the hinge 

 line, the shell was a little thicker, the hinge stronger, and the cardinal teeth larger, 

 not exceeding three ii. number and less oblique. In artificial casts of that species 

 the anterior muscular -MI proved to be comparatively larger, and to project farther 

 anterior to the filling of the beaks, which again are of larger size than in ninfn. I . 

 ! "iii of the iJalena belongs to the same group of -pecies but is a much larger 

 and rounder shell, and in casts has more compressed and less incurved beak-. 



.i/i-.ii me/ In-nitty. Tup <.f ihi- ue Beds," mid \>**- I.'IIJMT Huff !(<]." nf tin- 



.tn formation at I Min.-r;i; . -in. ami Uork' 



Mu*. Keg. No. 8321, 8325. 



\ \M \KMIA WOKTIU M I'lrirli. 



I-I.MI \\\ 



Cfprirarditrt s, 1888. I 



<->; wortheni 1'i.itifn. l. Ain.-r. '. 



Shell large, moderately ventrico-e. -ul.erect. snlicircular. the length a little 

 han the hight. the beaks nearly terminal, the dorsal margin aim ht, 



rather long and with the extremities rounding abruptly, th- or one 



projecting beyon<l the point of the beak*; f),,, n .,f ,,f \\ w outline rfnide<l with the 



-38 



