KM.ii:i: \N- in 0M 



.! 



In typo a-^ well. Imt this, unless we agree that tin- -h-rt -i'l- iii those 

 .illy the posterior, doe- not liriu^ them much nearer to the < '. >ill>,rtina type, 

 -UK,- the addm-tnr- an- iv \rrsed, the ariuninate-OVate SCar being anterior ill the 

 latter ami po-ti-rior in the farmer. 



.I/iff. A - in tin- iippr: :iati uroup at Clark*vllli- 



;iiul i.th.T :IM -..iiMli-d that ' '!.onwnU, Imt 



xl reasons to 1.. .: \. tliat It may be found In th< II .1- ata near Spring \ alley. 



KHODONTA Kll.i-'l i:i ATA, . 



ik-lit side of a cast of UP- inti-rmr of Ctentxlonla flIUtriala, n. up.: band <, rardinnl 

 and lateral virus ,,i i,-ft valve <>r -ami-: >/, small i>ort!<iM { surfiice of Hanic. highly in:inniil.-<l: e, liltt^i- 

 if a ri^'ht valv. U from lowvr U-<IH of thi- ('liiclnnall rnii]i at Ciivlni;t<iii, Ki-ntiirky: 



f ami /, '-ardlaal and la' i lar:r rlifht valve of Crnodnf>i ./iW^m/.i Salt.-r, fn-m thi' luw.-r 



Tri-nton ii'-ar Murfr^-sli- >fle. 



Tfllinomya Irvata HAI.I. and Wniii IKI.D, 1876. Pal. Ohio, vol. II, p. *_'. (Nut \nruln Imiln HAI.I . 



p. 150.) 



Tin may l>e distinguished at once from C. 'illx-rHna, with which it agrees 



more clo.-ely than any other known, by the delicate, crowded, thread-like concentric 

 lines which cover the entire surface. Twelve to twenty of these lines may be counted 

 in a space 1 mm. wide. The shape and general appearance of the shell is very simi- 

 lar in the two shells, but the basal margin in the present form is always uniformly 

 rounded, while the antero-dorsal angle i- a trifle !>lunter. The latter fact is due to 

 the greater bend in the hinge. The pit beneath the beak is scarcely so distinct as 

 in that species, and as the hinge is a little shorter the number of denticles is less 

 than the average number for C. albert inn, there being usually twelve anterior and 

 fifteen posterior. Finally, in perfect casts of the interior the beaks are not so much 

 compressed and the ridges running posteriorly from them less sharp. 



This species is generally identified with Mall's \iiniln or Tellinomya kvata, origin- 

 ally described from the Trenton limestone of New York, and closely related t 

 nitiiln of this report. The error of this identification i> so palpable that it is really 

 not worth the while to refute it. Any one at all capable of distinguishing species 

 must, now that attention has been directed to the matter, see at om > that the 

 shells are very different. 



t-.rmation and locality. In the lower beds of the Cinrinnati k'r >.! at numerou* IncalltlM lo and 

 [irinnati. A -m^lo specimen wan col T| SehocbMt In equivalent 



beds at Grander, Minnesota. 

 Reg. No. 8378. 



