NAniLITI^. 
153 
of Central Eussia, belongs to the same group of species. It differs 
from T. laius in having less numerous and rounder tubercles and 
fewer whorls. 
Unfortunately there is no record of the locality whence the fine 
specimen which represents this species in the Collection was obtained, 
though there is every probability that it came from the Coal-Mea- 
sures of Illinois. Meek and AYorthen’s type, it may be mentioned, 
was obtained at Carbon Cliff, Eock Island County, Illinois. 
Temnocheilus Coxanus, Meek and AYorthen. 
1870. Naufihis {Temnocheilus) Coxanus, Meek and AYorthen, Proc. 
Acad. Nat. Sci. Philadelphia, p. 50. 
1873. Nautilus {Temnocheilus) Coxanus^ Meek and AYorthen, Geol. 
Surv. of Illinois, vol. v. Palieont. p. 543, pi. xxiii. if. 1 a, 1 6. 
1883. Koj)hi7ioceras Coxanitm, Hyatt, Proc. Boston Soc. Nat. Hist, 
vol. xxii. p. 286. 
Sjy. Char. “ Shell rather small, subdiscoid, broadly rounded, or 
depressed convex over the periphery ; umbilicus wide, rather deep, 
perforated, and showing more than three-fourths of the dorso-ventral 
diameter of each inner turn ; volutions about two and a half to 
three, very slightly concave along the dorsal or inner side for tlio 
reception of the periphery of each succeeding turn within, more or 
less narrowly rounded (subangular in young specimens), and orna- 
mented by about fifteen small nodes around the middle of each side, 
from which point the inner side rounds very abruptly into the um- 
bilicus ; septa se})arated on the outer or ventral side by spaces one 
fifth to oiie sixth the transverse diameter of the volutions, at the 
point of measurement, arching slightly backwards in crossing the 
periphery ; body-chamber composing about half of the outer volu- 
tion ; si])huncle small and situated subcentrally, or somewhat nearer 
the outer or ventral side ; aperture transversely oval. Surface 
ornamented with distinct, regular, longitudinal raised lines, or small 
revolving costa), narrower than the rounded furrows between, those 
along the middle of the ventral or outer side being smaller and more 
crowded than those towards the lateral regions ; crossing all these 
are numerous very fine crowded stria) of growth, which curve 
strongly backward in passing over the periphery, parallel to the 
margins of the very profound sinus in the lip on the ventral side. 
“ Greatest diameter of a mature specimen 2-23 inches ; thickness, 
or transverse diameter, about 1 inch ; dorso-ventral diameter of last 
turn, near the aperture, 0-86 inch. 
“ Among the specimens before us there are two forms that may 
possibly belong to distinct species. One of these, which we con- 
