714 



ZOOLOGY 



SECT. 



commonly termed salivary, though their functional correspondence 

 with salivary glands has not been proved, are situated in the 

 head behind the cranial cartilage. The ducts of these two glands 

 run inwards and unite to form a median duct, which opens into 

 the buccal cavity. The name of liver (Fig. 624, //. ; Fig. 620, ///.) 

 or digestive viand is given to a large brown glandular mass 

 which extends from the neighbourhood of the salivary glands 



nearly to the aboral end of the 

 body. It consists of two com- 

 pletely independent right and 

 left portions, each of which has 

 a bile duct opening into the 

 cavity of the alimentary canal 

 opposite the point where stomach, 

 caecum, and intestine meet. Sur- 

 rounding the bile-ducts and 

 opening into them are masses of 

 minute vesicles (Fig. 624, l>. d.) ; 

 the secretion of these has the 

 property of converting starchy 

 matters into sugar; they some- 

 times, though without sufficient 

 reason, receive the name^ of 

 pancreas. 



Immediately below the thin 

 integument of the anterior wall 

 of the mantle-cavity lies a 

 characteristic organ- the ink- 

 sac (Fig. 626, ink s. ; Fig. 627). 

 This is a pear-shaped body, a 

 portion of the interior of which is 

 glandular and secretes a black 

 substance the ink or sepia 

 which collects in the main cavity 

 of the sac and is discharged by a 

 cylindrical duct opening into the 

 rectum close to the anal aperture. 

 When the Cuttle-fish is startled it discharges the ink, which, 

 mixing with the water in the mantle-cavity, is ejected through 

 the funnel as a black cloud, under cover of which the animal may 

 escape from a threatened attack. 



Vascular System. The heart (Figs. 025, 020, and 628) of 

 the Cuttle-fish consists of a ventricle' and two auricles. The 

 ventricle (vent.), which is divided into two lobes by a constric- 

 tion, is somewhat obliquely placed, but the rest of the vascular 

 system is almost completely equilateral. At its oral end the 

 ventricle gives off a large vessel the oral aorta (awt.) ; aborally 



Fi<;. 022. Sepia officinalis, jaws. A, 

 in situ; B, removed and slightly en- 

 larged. (From the O//</,,v'V/ c Natural 

 History.) 



