Mollusca — Cephalopoda. 
r* 
/b 
Gallery, 
No. 7 
on Plan. 
Cephalo- 
poda, 
Wall-case, 
No. 1. 
Table-case, 
No. 58. 
Belemnites. 
Wall-case, 
No. 14. 
Table-case, 
No. 58. 
Ink-bag - ol 
the Cuttle 
(Sepia). 
Beaks of 
Cuttle- 
fishes. 
Turrilites, 
Baculites 
etc. 
Most of them have a delicate internal shell, often quite 
minute, or rudimentary, as in Octopus, or divided into chambers 
by septa or partitions, as in Spirula. 
The delicate shells of Spirulirostra , Beloptera, &c. (Table- 
case, No. 58), occur in the Miocene and Eocene Strata. Im- 
pressions of “ Squids ” showing the soft parts of the bcdy, the 
arms, and the “ ink-bag” are found in the Chalk of the Lebanon, 
Syria; the Oxford Clay of Wiltshire; the Solenliofen limestone 
of Bavaria ; and the Lias of Lyme Regis, &c. (Table-case, .No. 
58; Wall-case, No. 1). 
The “ Belemnite,” so common a fossil in the Cretaceous and 
Oolitic rocks, is only the shelly extremity or “ guard ” (like the 
tip of a spear, or dart, without barbs), forming part of the 
internal shell of an extinct kind of Squid, or Cuttlefish, which, 
when perfect, had a chambered upper portion to its shell (called 
the phragmocone) , and a pearly extension beyond (called the 
pro-ostracum) . Some nearly perfect examples have been found 
in the Lias and Oxford Clay (see Wall-case). The arms 
were provided with booklets as well as suckers for holding fast 
its prey, and each animal had an ink-bag that secreted an inky 
fluid (known as sepia, and used as a pigment by artists), which 
could be ejected into the water at pleasure, so as to conceal the 
animal’s retreat by a cloud of inky blackness (Wall-case, No. 
14, and Table-case, No. 58). 
They all had strong horny or shelly mandibles, resembling a 
parrot’s beak ; these are frequently met with in a fossil state. 
By far the largest proportion of the fossil forms, however, 
belong to the Tetrabranchiate, or four-gilled division, repre- 
sented at the present day by the “ Pearly Nautilus ” of the Indian 
Ocean. These were less active forms than the Squids and 
Cuttlefishes ; and instead of having, like them, an internal 
shell, they had a strong external one with a pearly lining, in the 
large body-chamber of which the soft parts of the animal was 
enclosed. The rest of the shell is divided by septa or parti- 
tions into a series of chambers usually filled with fluid, through 
which a tube passes called the “ siphuncle.” These are merely 
the earlier and disused chambers of the animal’s shell which had 
been inhabited when it was younger, and have been gradually 
closed off and abandoned as the increased growth of its soft 
parts required a larger habitation. 
All the beautiful and varied forms of Turrilites , Baculites, 
Ammonites , Ceratites , Goniatites , Ortho ceratites , &c., belong to 
this great division of the Cephalopoda. 
The shells of the Pearly Nautilus have been obtained in 
large numbers from the London Clay of Highgate, Hampstead, 
and the Isle of Slieppy. Beautiful examples of these and of 
the little Nautilus ( Aturia ) zic-zac may be seen in the Table 
and Wall-cases. The Ammouites in infinite variety of pattern 
