DIVISION VI. SPIRULACEX. 
4. Spmvta. (1) Lam. 
The turns of the spire 
not touching ; divided 
transyersally into cham- 
bers. Pl. 4, fig. 18. 
2. Sprrouinites. Lam. 
The turns of the spire 
touching; the septa pro- 
GENERA. 
Siphon occupying the 
middle of each chamber 
and continued to the ex- 
tremity of the shell. 
Siphon traversing the 
septa and chambers. 
Ausiral Seas. Gulph 
of Florida. V. Animal, 
p. 4. 
Grignon. (2) 
jecting ina small degree, 
so as to divide the exterior 
surface of the spire by 
crests or strive. Pl. 1, fig. 
13. 
3. AmMonocenratites. (3) 
Lam. 
Rolled on itself in the 
same plane? 
Septa numerous, undu- Siphon marginal, in- 
lated at the margins. Pl. 3, terior. 
fig. 14. 
(1) Peron’s discovery of the animal of the Spirula, so nearly akin to the Nautili 
that Linnzus placed it amongst them, has thrown much light on all the multilocular 
univalves : thitherto, it was a question whether the animal inhabited the last 
chamber of the shell; whether it was contained entirely or partly within it; or 
whether the shell was enveloped more or less completely by the animal. The 
animal of the Spirula is perfectly analogous to the Sepia, and its shell is enchased 
in the posterior extremity of the body, and only visible in part. There is now very 
little, or no doubt, therefore, that the Rotalites, Belemnites, Hippurites, etc etc. 
were more or less enchased in the posterior extremity of the animal, a portion of 
whose body was enveloped in the last chamber, and connected, probably, by a 
tendinous filament inserted at the extremity of the siphon, similar to that of the 
Nautilus. Breynius, on the authority of Woodward (Catalogue of English Fossils. 
Part I, p. 113), says, that the shells of the Spirula abound on the shores of Jamaica, 
Barbadoes and the Bahamas: he adds, ‘‘de figura autem animalculi domicilium 
hoc testaceum curiosissimum inhabitantis, altum apud omnes silentium.” p. 22. 
(2) Lamarck has mentioned the genus Cristellaria (Pl. 3, fig. 13), but withoui 
defining it, and there are none in the Museum. These shells are cretaceous, and 
almost microscopic. Fossil species, pyritous or ferruginous, are found in Tuscany ; 
and M. Defrance possesses others, which are said to have been brought up with 
the soundings off Teneriffe. 
(3) The ep: is unknown. M. Lamarck purchased it by accident: he kindly 
allowed me to take it home, in order that the figure, whichis the first that has been 
made, might be as accurate as possible, 
