43 
NAUTILUS truncatus. 
TAB. CXXIIL 
Spec. Char. Thick, flatted, plain, umbilicate ; 
back flat,, mouth elongated, four-angled: si- 
phuncle nearest to the inner margin of the 
septum, 
Syn. Lister , 1048 . 
Thickness rather less than half the diameter ; the sides 
are rather conical and even. Mouth above half the dia- 
meter of the shell, long, narrowest towards the back, 
siphuncle oval. Septa very numerous, not recurved 
towards the umbilicus. 
A fine specimen of this species is figured by Lister, 
measuring ten inches in the longest diameter ; no doubt, 
when perfect it is sometimes much larger : mine is eight 
inches, I figure a part of it, as sufficient ; the remainder 
is a broken continuation of it. I have never seen the last 
chamber. This is composed of a mixture of dark lias lime- 
stone and pyrites, found at Keynsham, S. E. of Bristol. 
It is also said to be found in the blue lias of Bath, &c. 
Lister does not say where his specimen was found ; his 
figure shows about three whorls, mine did not expose 
them ; possibly when the shell is removed the whorls may 
be uncovered. Mine has fragments of the shell of consi- 
derable thickness about it, indicating that it was smooth 
when perfect. 
