172 
THE LIAS AMMONITES. 
Fig. 18. — Cliiroteuthis Veranyi, Ferussac. 
Fig. 19. — Sepia vermiculata, d'Orb. 
Fig. 20. 
Fig. 21. 
i 
Fig. 22. 
filled with air and supported by columns, but not perforated by a siphon (figs, 17 
and 19). 
4. i^flw^^7j/BELEMNITID7E, Owen, 1836. — An extinct family. Shell consisting of a pen, 
terminating posteriorly in a chambered cone, sometimes inclosed in a sheath or guard. 
The air-cells of the phragmacone are connected 
by a siphuncle close to the ventral side. The 
animal possessed an ink-bag, which is often 
found fossil in situ. The arms were provided 
with recurved booklets, seen in situ in speci- 
mens found in the Oxford Clay. The figures 
20, 21, 22, on the margin are ideal restora- 
tions of the animal of the Belemnites, and 
drawn by the late Professor Alcide d'Orbigny, 
who considered that the complete test of 
Belemnites was composed of four parts inti- 
mately united together. These parts are — 1st. 
Anteriorly a horny spatuliform blade, enlarged 
before and contracted behind. 2nd. A deep 
cup or conical alveolus containing a series of 
air-chambers. 3rd. An inferior siphon tra- 
versing the whole series of chambers. 4th. A 
calcareous sheath, more or less elongated, 
covering and protecting the alveolus, and con- 
stituting a true terminal rostrum, all which parts are shown in situ in the above figures 
of the restored forms. 
5. Family SpiRULiDyE, d' Orbipii/ , \'$>ol . — Body oblong, with small terminal fins; 
Fie;s. 20 — 22. — Belemnites restored by d'0rl)igny. 
