154 GUIDE TO THE FOSSIL INVERTEBRATE ANIMALS. 
Gallery 
VII. 
Table case 
I. 
Table-case 
1 . 
obscure the water ami protect the animal in its flight from 
an enemy. A [)aint made from this ink is called sepia, after 
the Latin nanie of the cnttle-ii.sh. The ink-hag is often 
found in these fos.sils, and its contents can still he used as a 
])aint. llehind the hody-chamher are seen the phragmocone 
and the guard, and stretching along the .sides of the whole 
shell are expansions of the mantle, forming fins. Belemnites 
Fig. 84. — Restoration of the animal and shell of belemnites. a, back 
view ; h, front or under view. (After d’Orbigny.) 
having this general structure and a solid guard lived to the 
close of the Cretaceous Epoch, when they disappeared. 
AVhereas the Ammonites left no descendants, the 
helemuites appear to have become changed into other forms. 
One of these, Beloscjna, is found in the Eocene London Clay 
(Fig. 85 d). Here the guard has become reduced in size, and 
the se])ta stretch in an upward curve from the apex of the 
shell (corresponding to the helemnite jdiragmocone) to the 
front of the pro-ostracum. They are numerous and close 
together. This form leads to the ordinary Sepia or cuttle- 
fish, of which two glass models are shown. The .shell of this 
