SWALLOW AND HAWN—THE ROCKs OF KANSAS. 187 
Monotis raprauis, Phillips, Enc. Met 
oe ay RADIALIS, , King, Per. Fos., p. (157, pl. xm1., figs. 
Our specimens are identical with those figured and described 
. King and Phillips 
y Messrs an ps. 
Be Hawn’'s collection from the be Permian strata, 
near Smoky-Hill Fork, K. T. 
Moxorts VARIABILIS, Swallow. 
Shell variable, oblique, ee transversely monet 
ovate; left valve more or less regularly arche 
namented with fine , radiating a7 peices strie ; on the 
ventral and lateral margins are variable, radiating ged 
and a9 coste extending ay one-fourth to one-half of 
ce from the margin to the beak, where they entnely 
ear; beak small, Scud depressed, oe to 
er or a little beyond; the whole surface is marked with 
concentric lines of growth; Sodeaal margin .-obhahe, poste- 
rior part more so than the gaesh slight sinus below the an- 
terior wing. Right valve not see 
$ species is very easily Fistinguiskied by the peculiarity 
markings, by the smooth, finely-decussated visceral re- 
and t \igethomedeed costate and spinose or nny m 
is very variable in form. 
, 0.88; height, from beak to the anterior margin, 
bles the shpat: Phillips, i in form ; but i it 
ently mark 
a llection from ar 8 Permian Rocks, : 
ley of the Cotton-wood, K. 
aie PRmMIANUb; = Stn see A 
