100 
XA.UIILOIDEA. 
periphery ; the next has a much more acute periphery, and is corre- 
spondingly embraced by the succeeding turn.” {M^Coy.) 
Remarhs. It 'vrill be seen that the whorls in the young of this 
species are, as already pointed out by Professor Hyatt, similar to 
the adult of Discites both in form and ornamentation. The lenticular 
form of the whorl recalls also the Nautilus discus of Sowerby. 
There is no species with which the present one is strictly com- 
parable. 
Horizon. Carboniferous Limestone. 
Locality. Unknown. 
Kepresented in the Collection by a single example, contained in 
the Gilbertson Collection.” 
Genus EPHIPPIOCER AS \ Hyatt =. 
(Nautilus (pars), aiictoium.') 
Pig. 13. 
Ephqypiocems clifellariiim. — a, ventral or peripheral view of a cast, showing 
the septa and the faint median line ; the dotted lines are added to indicate 
the form of the shell when perfect : b, lateral view of the same fragment. 
Drawn from a specimen in the Collection. Natural size. 
Gen. Char. Shell iVaut<7i(s-like, globose, rapidly enlarging, very 
slightly umbilicated, if at all. Septa forming a verj^ acute angle 
upon the periphery, so that they divide the shell into two elliptical 
^ From 6(pi7nriov, a saddle. 
“ Proc. Boston Soc. Nat. Hist. 1883, vol. xxii. p. 29U. 
