THE ECONOMIC MOLLUSC A OF ACADIA. 



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, iit the posterior end, 

 attached on the dorsal side, is the broad 

 caudal fin 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 two radii sloping to the extreme pos- Fig. I. 

 terior end. An average specimen is fourteen 

 inches in extreme length, the body proper 

 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 out&ide 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 ia 

 this species. Prof. Verrill says:—" The colors change constantly, whem 



-Ommastrephes il- 

 lecehrom. Young male,, 

 three-sevenths of natural 

 size. 



