r 
xAuirLiD^. 129 
the ventro-dorsal diameter. The siphimcle is unknown. The sur- 
face of the test appears to he perfectly smooth. 
Xeither of the forms figured by Phillips belong to the present 
species, and they are also evidently distinct from each other. 
The fragment of the body-chamber (Geol. of Yorkshire, pt. ii. 
pi. xvii. f. 28) now in the “ Gilbertson Collection ” in the British 
Museum is too imperfect for identification. 
Pig. 20. 
Coelonautilus glohatus. — a, lateral view, showing the deeply excavated umbilicus ; 
h, front view, showing the pinched form of the aperture and the keeled 
edge of the umbilicus ; the siphnncle is seen where a portion of the shell 
has been broken away. Drawn from a specimen in the Collection, About 
one half the natural size. 
Sowerby’s figures do not show the angular, almost keeled cha- 
racter of the umbilical margin, all his specimens having the umbi- 
licus filled with matrix. It is probably owing to this that M‘Coy^ 
and other authors have mistaken other species for glohatus. Both 
M‘Coy and de Koninck regard the bistrialis of Phillips as identical 
with the present species, but I think it can be clearly shown that 
the two are distinct. 
Messrs. Meek and Worthen (Geol. of Illinois, vol. ii. loc. cit.) 
describe their form as differing from Sowerby’s species only in the 
size of the siphnncle, which is smaller in the American form than 
in the English, judging by M‘Coy’s description of it in the ‘ British 
Palaeozoic Possils ’ (p. 559). But as M‘Coy in that work was not 
^ In ‘ British Palasozoic Fossils,’ 1855, Sedgwick and M'Coy, p. 558, but not 
in the ‘ Synopsis of the Carboniferous Fossils of Ireland,’ 1844, p. 21. 
PAKT II. K 
