THE ECONOMIC MOLLUSCA OF ACADIA. 
2 5 > 
Habits. The Squid is easily recognized and is one of the best 
known of our Molluscs. It is the most highly organized of the group,, 
and in its appearance and most of its habits, 
resembles a fish rather than what it really is. 
The body is cylindrical, tapering to a 
point at the posterior end, and in front bears 
a head which has ten arms arranged in a ring 
around the mouth. These arms bear sucking 
disks on their inner sides, in the two longer 
near their extremities only, and in the other 
eight quite to their bases. The mouth is arm- 
ed with a stout horny beak similar to that of 
a parrot. The large and very bright eyes are 
on diametrically opposite sides of the head; 
they have lids and a round pupil. The neck 
is well marked, sharply separating the head 
from the body. On the under side of the 
latter, projecting forward, is a stout process 
with an opening at its apex which might be 
mistaken for a mouth. It is the opening of 
the tube or siphon by which water is drawn 
into and expelled from a sac inside the body, 
this being, as will be explained below, its 
locomotive apparatus. At the posterior end, 
attached on the dorsal side, is the broad 
caudal tin which extends a little more than a 
third (about two-fifths) of the length of the 
body proper. It extends out laterally on each 
side of the latter and is shaped like the quad- 
rant of a circle, the arc being to the front 
and the tw T o radii sloping to the extreme pos- Fig. I. Ommastrephes il- 
terior end. An average specimen is fourteen tWMv'ent£Tnato?S' 
inches in extreme length, the body proper size, 
being eight inches; length of fin about three inches; body one and one- 
half inches in diameter. 
In the interior on the back of the animal, and running the entire 
length of the body, is a translucent, horny pen-shaped structure, called 
the “ pen.” This is in reality the shell, reduced and carried inward 
nstead of covering the outside of the animal. 
The color is variable in the extreme. The ground color is pale- 
bluish-white, and in the skin are many chromatophores, or cells 
containing colored pigments, any set of which can be expanded 
or contracted at the will of the animal. It is thus that the rapid changes- 
of color are caused— red, orange and brown seeming to predominate in 
this species. Prof. Verrill says: — “ The colors change constantly, when* 
