

.illy much nearer (<i tin- forms now referred to the p-im-. than I was inclined to 

 Mieve two ye. i 



1 !' ' valves u f a closely related sp,.,-j,.s or \ ariet y from t lie lower t hird 



of tin- Trenton shale-, at Minneapolis. and another, .-lightly longer than the 

 from the upper third near C.innon I'. ill- specimens are le-> lii^'h than the 



'iinil'ilnntiia. the ventral margin I" The anterior end al-o 



isatritle narrower, and the convexity of (lie valves somewhat less, while none of 

 them -how anv thing of the grannlose surface ornament nor of the marginal papilla'. 

 These -pecnnens may provisionally lie known a- \ar. .NK..I.KI-TI -. 



The straight l.aek and dorsal an-le- will at once distinguish l.otli the >pecie> 

 and variety from .1. fll'ipti. 



' i nneaotA. Var." ntglecttu 



ir^ In th.' IIIW.T thin! f tin; slialcs ;ii Mmn.-;i|. 



AI-.M;. HI: K- Mii.i.KiTM-rvTrs I'frirli. 



ri.ATK .r. Ift-W. 



lilin mi! I UlWtOE X, p. 268. 



< '!: \ nun: liitflit 1.0 linn.: Uii.-kn.',M.J-J iniii. 



Valve> MiMliptical. .lor.-al margin lon^. -trai^ht; ends rounded from the dorsil 

 e<. equal: ventral edges bevelled inw >\nt of greatest convexity a little 



behind and l-eneath the ini'ldle: surface very finely punctate. 



This -p, .,;,.> j. smaller than .1. <iranilnlnnlus, but relatively longer, and more 



uniformly convex. In its outline it is similar to Is-perd'tieHa tnjnihilcra I'lrich. from 



the Hirdseye limestone of Kentucky (see fig. 4U. p. C.:1G), but it is a little higher, has 



led and not overlap). ing edges, and a puiirtat. n which is wanting in that 



nation and locality. Lciwi-rur iniildlr third t ->n shales, near FounUn 



/ 'I rich. 



I'l.^ U. 



i ftmhrinln I'I.KI. n ]s;.j. .\II.-T 



i i: \ i L<'ntfth l.ss mm.: hikrlit l.i'l mm.; thii-ku.>s(i.4 IIIIH. 



Valves siiUval. moderately and almost uniformly convex; Lack strai-ht. nearly 

 rhirds as long as the valve: dorsal -li.irp. a -liL'ht swelling of the M,, 



immediately l.eneath them caiisiu- them t. inewhat ].rominei/ 



'y equally rounded, the posterior a litt ! the u i.ler. The entire ventral t... 

 and the end-, excepting the upper third on each -\<\<\ with a frin,.' 3 of 



long, almost p.iliform. processes, separated l.y intervals of n.l mm. or less. 



