354 LECTURE XXIV. 



of membrane. In some of the Calamaries, in which the superior sali- 

 vary glands penetrate the folds, the ducts open upon the inner surface, 

 as in the Nautihis. In the Octopus the anterior or upper salivary 

 glands are on the outside of the buccal mass. In most of the Dibran- 

 chiata a second and larger pair of salivary glands is situated on each 

 side of the oesophagus, at the commencement of the abdominal or 

 hepatic cavity ; their ducts unite to terminate below the tongue in the 

 concavity of the lower mandible. 



The peritoneal membrane is divided and disposed as in the Nau- 

 tilus, in order to form special receptacles for the different viscera. 

 The oesophagus is narrower than in the Nautilus, and provided 

 with longitudinal plicae : it dilates soon after having passed through 

 the cranium into a long ingluvies, forming a large cul-de-sac at 

 its commencement in both the Octopus and Argonaut ; but in the 

 Decapods it continues narrow and of uniform breadth to the stomach. 

 This cavity (A) is an elongated sac, presenting, in the disposition of 

 its muscular fibres, in the proximity of the cardiac and pyloric orifices, 

 and in the thickness of the epithelial lining, the usual characters of 

 the gizzard. The intestine, at a short distance from the pylorus, com- 

 municates with a glandular and laminated sac (q) analogous to that 

 in the Nautilus, and presenting a similar globular form in the Rossia 

 and Loligopsis ; but elongated and spirally convoluted in the Sepia 

 and Loligo. It receives the biliary secretion between two broad 

 lamellae, as in the Nautilus. The intestine is very short in all the 

 Dibranchiata. In the Octopus it is bent upon itself (?•), as in the 

 Nautilus ; but in the Sepia and Loligo it is continued forwards in a 

 straight line, from the stomach to the vent. Its internal membrane 

 is longitudinally folded, but is smooth at the short tract beyond the 

 enti'y of the duct of the ink-bag; its termination is constricted either 

 by the muscular fibres of the branchial septum, or by those which 

 connect together the pillars of the funnel. In the Decapods provided 

 with fins for swimming forwards, the anus can be closed by tri- 

 angular fleshy valves ; and in some species these are modified into 

 the form of antennal filaments. 



The liver (a^) is of large size in the Dibranchiata, but of more 

 simple form than in the Nautilus. In the Sepia it is divided into 

 two lateral lobes, Avhich are notched at the upper extremity ; in the 

 Onychoteuthis it is a simple, elongated, compressed lobe with un- 

 divided extremities: in tlie Octopus it forms a single oval mass, 

 flattened anteriorly : in the Eledone it is spherical, corresponding with 

 the ventricose visceral sac. In the two latter genera the ink-bag (d) 

 is enclosed within the capsule of the liver, and was naturally mistaken 

 for the gall-bladder by some of the early anatomists of these Mol- 



