MOLLUSCA.—CLASS V. CEPHALOPODA. 283 
dorsal part of the body, and in some it assumes a lanceolate, transparent 
structure like a glass feather. In Spirula the shell is inserted within the 
posterior extremity of the abdominal sack, and may probably be destined 
to have a certain hydrostatic influence on the movements of its owner. 
Nothing, however, is known of this animal beyond the record of a single 
individual, and although the discoveries of M. Péron have been quoted 
with considerable assurance by continental writers, they yet remain to be 
confirmed. A very extensive group of minute chambered bodies has also 
been attributed to animals of similar nature to the Cephalopods, on account 
of their cellular construction, though presenting a singular anomaly of dis- 
position. 
Gualtieri was the first to include the Foraminifera in this class, and 
upon the discovery of the living Spirula, by Péron and Lesueur, Lamarck 
and others immediately convinced themselves that he was right. They 
felt persuaded that these minute cellular bodies were the shells of animals 
similarly circumstanced. ‘‘ Ce fut done rendre un service bien important é 
> 
la science,” says Lamarck, ‘‘je me crus autorisé a le regarder comme le 
type des animaux qui produisent les Coquilles multiloculares, et enfin a con- 
clure que toutes ces Coquilles appartiennent a des Cephalopodes ;’’ and Des- 
hayes, no doubt encouraged in this belief by the ingenious examination 
of them by D’Orbigny, says, ‘‘ C’est sans contredit l'un des faits les plus 
mmportans dont la science se soit enrichie, que celui rélatif a la Spirule ; les 
doutes que Von pouvoit conserver, sur la nature de beaucoup de genres deve- 
noient désormais impossibles.” 
The testimony of these writers is so strong on this head, that we have 
been fearful to exclude these foraminiferous cells from the class; it is, 
however, strongly suspected that they are deposited by the Radiata, or 
some other animals of inferior organization*. 
The habits of the Cephalopods have been spoken of with much enthu- 
siasm by travellers ; no molluscous animals of their size are so abundantly 
prolific, or so widely distributed over the globe. They mostly inhabit 
* Philippi has had less hesitation than ourselves on this point, and perhaps with judgment. 
** Sie dicta Polythalamia,” says that writer im his Introduction to ‘ The Shells of Sicily,’ ‘« hic 
omisi, quia ea nullo modo Molluscis adscribi posse credo.” 
