256 Description of a Species of Caligus. 
The intestinal fluids are usually light yellow ; occasionally they 
present a deep wine yellow color, especially below the sternum of 
the second pair of natatories. Solid vermiform masses of a brown 
color, are often seen floating in the fluids. 
Along the alimentary canal, there are several small glands, 
which have a granulous structure and are in general but slightly 
colored. Their particular functions, are mostly conjectural. 
~ The central projection between g, g, fig. 12, is the termination 
of a gland of considerable size, which is situated beneath the pos- 
terior extremity of the buccal mass, and is usually detached with 
it, on dissection. It is represented in fig. 9, a, where its size cor- 
responds to the mouth in fig. 9. When separated from the mouth, 
a duct may be seen on each side, entering the mouth near the 
esophagus. Anterior to the mouth, another collection of glands 
is observed, (fig. 9, b, see also fig. 1,) which also communicate 
with the mouth by ducts. These are probably salivary glands. 
The esophagus, especially near its base, is furnished with a 
large number of exceedingly minute, transparent globules, sup- 
ported on short pedicels, (fig. 10, Pl. IV.) These appear to be 
s, and their pedicels ducts. 
Below the stomach in the thorax, there are four pairs of glands. 
One pair of nearly spherical form, are situated at the lower extrem- 
ity of the stomach, (c, fig. 9.) The second pair, larger, of an 
oblong form, (d,) occur just below the sternum of the first pair of 
natatories, and are connected with the intestine by a duct under 
the following sternum. The third and fourth pairs, (e, f,) are sit- 
uated on the enlargement of the intestine, below the sternum of 
the second pair of natatories. The functions of a liver are prob- 
ably performed by some or all of these glands. 
Two other pairs of small glands are situated in the abdomen, 
which we présume to be connected with the intestine ; we have 
not however distinguished their ducts, neither have we by dissec- 
tions obtained more than one of them separate from the body: 
They are possibly urinary glands. 
The Caligi have heretofore been supposed to live by sucking 
the blood of the fish on which they are found. It is however 
apparent from the structure of the mouth, that they are wholly 
unfitted for this mode of life. There is no organ which can per 
form the functions of a sucker. Moreover, we have never detect- 
