PHOLADID/E. 
389 
Opposing unassailable reasons against two theories, the learned author 
f °es not leave us without a very reasonable explanation of a very 
Puzzling phenomenon. “Let us not forget,” he says, “that the 
Ulterior of the gallery is constantly saturated with water ; consequently 
the points of the walls which are not protected by the tube are 
objected to constant maceration. In this state a mechanical action, 
6ven very inconsiderable, would suffice to clear away the bed of fibre 
us softened, and, if this action is in any degree continuous, it suf- 
Ces to explain the excavation of the galleries, however extensive their 
r uinifications. Again, the upper cutaneous folds, 
specially the cephalic hood already mentioned, hav- 
| r jg the power of expanding at will by an afflux of 
*°od, covered with a thick coriaceous epidermis, and 
Uioved by four strong muscles, seems to me very 
Ca Pable of performing the operation. It appears very 
Probable that it is this hood which is charged with 
Ue removal of the woody fibre, rendering it incapable 
resistance by previous maceration, which may also 
6 assisted by some secretion from the animal.” That 
H; fleshy parts of the mollusc, acting upon the 
Urface, softened by long maceration in water, is the 
Ue boring implement employed by the Teredo, is, 
P r °bably, the only explanation the case admits of; at 
events, in the present state of our knowledge, the 
ex planation of the learned naturalist is the most 
l ' e asonable which can be "iven. 
As an appendage to the history of the Teredo, we 
, here add a few words on a very curious animal, 
j, Uc h has received the strange name of the Watering 
^(Aspergillum). This animal, which is represented 
.8* * 79, inhabits a calcareous tube, thick, solid of 
^Usiderable length, and nearly cylindrical, presenting 
f °ne extremity an opening fringed with one or many 
^aceoug folds in the form of frills, and at the other 
* at le “% a convex disk, pierced with holes like a 
m erm S-P°t : whence its name. The animal is attached by certain 
Sc es to the interior of the tube. Chenu, to whom we are in- 
Fig. IV 9. Asp 
vaginiferum (L; 
