It is unnecessary to allude to the obvious utility of this structure in seizing the morsels of food, and directing them towards the gullet, after they have been broken up by the mandi bles. Behind this homy part the tongue again becomes soft and papillose (I), but the papillm are coarser and larger than those on the anterior portions. Two broad fleshy processes (g, g,) project forwards from the sides of the fauces : these also are papillose, and are perforated in the middle of their inner surfaces by a small aperture (h, h), which leads into a glandular cavity, situated between the folds of the mem brane, and analogous to the superior pair of salivary glands in the Poulp, Calamaries, &c.
In the Dibranchiate Cephalopods the tongue is similarly composed of an anterior and pos terior papillose and a middle spiny portion. In the specimen from which the figure (218) was taken, the anterior fleshy portion (e) was slightly divided into three parts, but was retracted by a single round muscle, and the papillm were relatively fewer and coarser than in the Nautilus : at its sides there were several orifices of glandular follicles. The horny plate, covering the middle part of the tong,ue, is bent at right angles ; the recurved hooks in the Onychoteuthis are confined to the anterior and vertical surface ; they commence above or be hind in seven rows; but, as they descend, first the two outer on each side blend together, and then each united row joins the next, so that there remain but three rows at the lower part of the sheath. In the Cuttle-fish the seven rows of lingual spines continue distinct.
In the Onychoteuthis the posterior portion of the tongue (g) is inclosed, as in the Nau tilus, between two faucial or pharyngeal folds of membrane (h, h), but their inner surfaces, instead of being merely papillose, are beset with rows of small recurved spines, which must greatly assist the act of deglutition.
The superior salivary glands (i) are not con fined to the outside of the buccal mass, as in the Octopus, but extend between the layers of membrane which form the pharyngeal fold, forming here a flattened mass (i); their duct opens at the bottom of a longitudinal fissure on the inner surface of the fold ; styles are repre sented passing into the ducts of these glands in the figure.
In most of the Dibranchiata a second and generally larger pair of salivary glands are found below the cartilaginous cranium, situ ated in the hepatic cavity, on either side of the cesophagus. A single excretory duct is continued from each gland, and the two unite and form one, as they are passing through the cranium. The common duct penetrates the
lower or central surface of the buccal mass, and is continued along the concavity of the lower mandible, through the tongue to the lower part of the spiny plate, where it termin ates. In the Octopus these glands are very large, and have a smooth surface (q, fig. 233) ; but in many Cephalopods, as in Ocythoi, Sepiola, and Rossia, they are relatively smaller, and have a granular surface. It is in the genus Loligopsis alone that these glands have hither to been found wanting.
With respect to the ultimate structure of the salivary glands of the Cephalopoda, Muller* observes that they are not composed of solid acini or granules, but of hollow canals or cells.
Before the description of the abdominal viscera is proceeded with, it is necessary to make a few observations on their position and connections.
In the ventricose and short-bodied species of Cephalopoda the mantle-sac is almost wholly filled with the viscera, but in those of an elon gated form they are more or less confined to the lower part of the sac, and a vacant space intervenes between the visceral mass and the opening of the mantle, which is traversed by the respiratory currents : the part of the mantle unoccupied by the viscera is most remarkable for its extent in the genus Loligopsis (jig. 223.) If the mantle of the common Octopus or Poulp be laid open longitudinally, and a little to one side of the mesial line, a cavity will be exposed, separated by the longitudinal musculir septum (c,fig.216) from the corresponding one of the opposite side; in these two cavities are contained the branchim (r,fig. 216), the termi nations of the oviducts (p ), and the pericardial apertures (q). Below and behind the branchial cavities, the peritoneum is seen enveloping the rest of the viscera ; but this great serous sac is subdivided into many compartments. If the point of the scissors be inserted into the project ing orifice internal to the root of the gill (i,.fig. 226), and the cavity of which it is the outlet be laid open, the branchial ventricle, the branchial division of the vena cava, and its appended follicles will be exposed ; this cavity is sepa rated from a corresponding one on the opposite side by the systemic heart and the great vessels, which are contained in a distinct serous com nartment. In the Nmitilro; thp turn latarn1 the middle cavities form one large pericardiac chamber, appropriated to the heart and great vessels, and the venous appendages.