228 DENTALIAD. 
very minute Foraminifera,—a convincing proof of the voracity 
of these animals. I have never failed to find in them either 
the Quinque-, Tri-, or Bi-loculine, or the Rotalia Beccarii, the 
Lobatula vulgaris, Bulimina pulchella, Textularia oblonga, 
Lagena amphora, or the Robulina subcultrata, and more rarely 
a minute bivalve, either the Kellia suborbicularis or Astarte 
triangularis : this fact is another proof, if any additional ones 
were necessary, that an animal inhabits the minute calcareous 
forms which were formerly supposed to enclose Cephalopoda, 
or to be inserted in their membranes; they are not mhabit- 
ants of the littoral, but of the coralline zones, and appear 
to be the sole aliment of this decided zoophagous mollusc. 
These shells are in transitu to be acted on by the appendage 
within the stomach, which will be noticed shortly, and after 
having undergone its action the rejectamenta are discharged 
anteriorly with other mucal and feecal matters, and not at the 
posterior terminus agreeably to M. Deshayes’ determination ; 
and I shall presently demonstrate that the posterior aperture 
is not for anal uses, but to supply the branchize with water. 
It is now necessary to mention the figure and situation of 
the heart and branchiz ; these pomts must be carefully kept 
in mind, as the demonstration I propose rests on a due consi- 
deration of them. The heart is a subrotund minute ventricle 
with a linear depression on its summit, and when opened 
shows the corresponding ridge; its surface is fortified with 
muscular raised lines ; it is fixed centrally at the posterior end 
of the branchial cavity and base of the stomach, and in some 
transparent animals may be seen in the pericardium ; in the 
very young pellucid shells seven inspirations and as many 
nearly isochronal expirations have been counted in a minute, 
and the corresponding ingress and egress of the water seen *. 
* Lamarck, in the last edit. of the ‘Anim. sans Vert.’ (Milne-Edwards’s) 
3rd vol. p. 13, says, “ Car, aprés les animaux vertébrés, la nature n’offre, 
dans aucun animal, ces mouvements alternatifs et mesurés d’inspiration 
et d’expiration du fluide inspiré,” &ce. 
On this point that great naturalist is m error, as in Dentalium Tarenti- 
num I have, with a chronometer showing seconds, repeatedly marked nearly 
isochronal inspirations and expirations of the aérating fluid, the two toge- 
ther amounting to about sixteen in a minute. 
