236 SUPPLEMENT 
torial than in the polar. This is still more evident with the 
biphore, which do not even commence to appear but in the 
seas of temperate regions. 
The class of the oscabriones has species in all seas, but 
much more numerous and larger in those of hot countries than 
in others. 
It is almost nearly the same thing with those of the class of 
the nematopods. 
We likewise may say of the families, the genera, and spe- 
cies of the acephala, what we have said of the others, that 
although more numerous, and of larger dimensions in the 
equatorial zones, the genera are represented in all, with few 
exceptions. 
The relations of the animals of this type with others are not 
in general very favourable to them; in other words, they are 
more often obliged to fly than to seek them; and though a 
certain number of them are zoophagous, there are few which 
attack animals of the higher classes. Perhaps there are none 
which do so except the brachiocephala, which feed on crus- 
tacea and fish. All the other zoophagous species attack only 
animals of their own class, and especially of the class of the 
acephala, which move with difficulty. Accordingly, we may 
say in a general manner, that the type of the malacozoaria 
exercise but a feeble action on the preceding types, while the 
latter, on the contrary, exercise upon it a very destructive one. 
In fact, a certain number of aquatic mammifera, as the ceta- 
cea, the morses, but above all, the birds which inhabit the 
waters, the amphibious animals, and even the fish, pursue with 
more or less avidity the naked or conchyliferous mollusca, 
break the shell of the latter, and devour them. Accordingly, 
this group of animals does not appear to escape destruction, 
except from the places which they inhabit, and the immensity 
of their multiplication. 
