1. \MKI.1.1HK.\N- IIIA "'t'.l 



Vumnrmla ) 



f plate XU repre-eiif- what a] . > !> a large ri^-lit valve of gtrv 

 Tin' specimen i- preserved as a partial mould of the exterior. Another -perimen 

 fnun t!i> lialena near Wykoll may l>e -aid to he identical in it- characters with the 

 original types of gerwtinn. The >p(>riiiu>ii represented l.y tig. 10 is one of a number 

 in which the Balance of agreements i> with the variety rather than with typical 

 ynimlis. while tin- original of fig. 11 was made \<y a -mall right valve of which tin- 

 opposite SQein- to he true. 



>ther \ariety wa> found in the Trenton of -ee by Prof. Jas. M. Saflord, 



ami sent to m<> for examination. The illustrations -how that in its outline and 

 general appearance this new \. riety gernutna and ('Jfiiflla. 



It differs, however, in the teeth which are stronger and more curve-1 than in those 

 forms, being on the whole more like those of ( '. ,/r.indis and C. *///<//. As it marks 

 another -ta^e in the development of this type of shells it should receive a name. I 

 propose therefore that it l>e called < 'i/rtmlnnfu i/rnntlix, var. ind-riHnlin. 



Mr. Sardeson has Driven the name Inmli-nt'i doc. cit.) to a Hudson River form of 

 which the hin^e and exterior of two fair examples are represented on Plate XL, by 

 figs. 1:5 and 1 J. This form I cannot now regard as specifically distinct from C. yrandis, 

 -ince it is almost identical with var. : / -inana, the only dillerence being small ones 

 in the hinge and that the umbones are somewhat larger in the luculeiiln. 



Two other stages in the development of this series of shells, in these cases per- 

 haps of specific importance, occur in the upper beds of the Cincinnati group at Nirh- 

 mond, Indiana. These I hope to describe in another publication. 



P,>rmntiiin an>t lnrtilil>j.-'l: f C. grandit and the var. germana, are fnun tin- u|i|HTTi 



. Ii.uivill,'. K.-ntii.'kv. Ca-i- "f 1 he species and variety have Ix-vn found in th' middle 

 and ; Wyktiff, Linn- Ciiy, and otln-r liK-.ilitli ID 



Mlm 'media ! o far km.wi. 



fn.in th-- 'I - null, in T.Tin.-sscc, when- it i.'-i-ur- in a -i;il mil with I 



ily llmiUtni-i..f tip II -r group at Granger and 



ntlu-r - in Fllliiion* count " - >ta. 



Mu. K*g. Nt*. > S380, 8333. Var. luculenta "332. 



DUfl \ AM XKMIA. Hillings. 



r.mujrmui, lln.i P l. 



ico-e. olili|iie. acuminate ovate to -nil.circular; anterior end very short 

 and small, the posterior l.roadly rounded. I'mLone- full, prominent, \yosiks strongly 

 incurved. Surface with concentric growth lines only. Hin^e -tron^. with teeth 

 as in Ci/H'xl-mf'i. two to four, rarely more, cardinal, and two to four posterior lat> 

 teeth in each valve. T. iuently striated tra- B elongated ligUMBta] 



area generally | Iductors. the anterior depnion very -harply delined 



and deep, and -ituatod in a prolongation from the anterior end of the hinp- \ 



