REPORT OF COMMISSIONER OF FISH AND FISHERIES. [ 98 ] 
young mackerel were mostly 8 to 10 inclies long, and some of them were 
still larger. 
This species, like the common Loligo , has the instincts and habits of 
a cannibal, for small squids of its own species form one of the most com¬ 
mon articles of its diet. From an adult female of ordinary size (G, of our 
tables), caught at Eastport, Me., I took a great mass of fragments of 
small squids, with which the stomach was greatly distended. These 
fragments completely filled a vial having a capacity of four fluid ounces. 
From the rapidity with which the squids devour the fish that they 
capture, it is evident that the jaws are the principal organs used, and 
that the odontophore plays only a subordinate part in feeding. This is 
confirmed by the condition of the food ordinarily found in the stomach, 
for both the fishes and the shrimp are usually in fragments and shreds 
of some size, and smaller creatures, like Amphipods, are often found 
entire, or nearly so; even the vertebrae and other bones of herring are 
often present. On the other hand, in some specimens, the contents of 
the stomach are finely divided, as if the odontophore had been used for 
that purpose. 
Notes on the visceral anatomy. 
Plate XIX, figure 1. Plate XX, figure 1. 
This species, in common with others of the same genus, is very differ¬ 
ent from Loligo Pealei in the form and structure of many of its internal 
organs. The branchial cavity is larger and the gills (g, g) originate farther 
back and are much larger than in Loligo , their length being about two- 
fifths the entire length of the body; they originate back nearly at the 
middle of the body. The liver (l, l) is much larger and more conspicu¬ 
ous, consisting of two large, oblong, lateral lobes or masses, closely 
united together in the median plane, with a groove along the dorsal side, 
in which lies the oesophagus. The ink-bag ( i) is elongated-pyriform, 
with a silvery luster externally, but blackish when filled with the ink. 
The size and form of the stomach and its ccecal lobe (s, s') vary greatly 
according to their degree of distention with food. When well filled 
they are very large, saccular, and more or less pyriform, the ccecal lobe 
extending back nearly to the end of the body. The walls of the stomach 
are in part thick, muscular, and longitudinally plicated within. The in¬ 
testine (h) has two spatulate papillae, one on each side of the anal orifice. 
The heart ( E ) is large, somewhat irregular and unsymmetrical, with 
four points, the two lateral continuous with the afferent vessels (bo) of 
the gills 5 the anterior passing into the anterior aorta ( ao ); the poste¬ 
rior median one, continuous with the posterior aorta, gives off first a 
small ventral branch, which supplies the reproductive organs, and then, 
later, a median ventral artery (o), going to the mantlej while much far¬ 
ther back it divides into two branches (o', o'), which supply the sides of 
the mantle and caudal fin. The branchial auricles ( an ) are large and 
ovate, with a small, round capsule at the posterior end. 
The anterior urinary organs or ‘kidneys’ (r, r) are voluminous, deeply 
