34 



duct," which runs forward along-side (he oesophagus to 

 the buccal mass (fig. 17). 



The sub-lingual gland is oval, and thickened 

 posteriorly (PI. IV, fig. 23, s.l.g.). In those Cephalopods 

 whose development has been studied, it arises as an 

 infolding of the ventral wall of the pharynx of the 

 embryo, below and anterior to the sub-radular organ. 

 This infolded region then gives rise to many tubular 

 caeca, each of which opens independently by a minute 

 opening into the buccal cavity. These tubules, connected 

 together by indifferent tissue, thus form the compacl 

 sub-lingual gland. The three salivary glands all consist 

 of glandular secretory tubules, embedded in a stroma of 

 connective tissue (PI. V, figs. 34 and 35, Tu., Str.). 

 These tubules are closely adpressed in the anterior glands, 

 but much further apart in the posterior glands, and 

 branch dichotomously here (figs. 85 and 34). The 

 secretory cells of the three glands are all similar, and are 

 columnar with a basal nucleus. The secretion forms in 

 globules in the anterior portion of the cell, and then falls 

 into the lumen of the tubule (PI. Y, fig. 36). The 

 secretion of these glands is a kind of mucus only, and 

 contains no ferment whatever (Fredericq and Bourquelot). 

 The venous blood, collecting in the sinuses occurring in 

 the stroma of connective tissue which binds the secretory 

 tubules together, passes out directly into the perivisceral 

 venous sinus. 



Stomach. This is a very muscular grinding organ, 

 reminding one of the gizzard of a bird. Its ventral and 

 dorsal walls are thickened anteriorly into grinding pads. 

 These are thick and stout, and ridged internally. The 

 posterior and lateral walls are, however, thinner. The 

 oesophagus opens into the stomach at its right anterioi 

 angle, and the origin of the spiral caecum and iniesiine 



