470 SANGUIFEROUS SYSTEM, 



zard, and penetrating a foramen of the muscular diaphragm, 

 it ascends on the right side of the oesophagus, in the dorsal 

 cavity behind the liver, as far as the oesophageal opening of 

 the cranium. Near its commencement this great trunk gives 

 off a peritoneal branch, then two dorsal palleal branches, 

 then some twigs to the gizzard, a little higher a branch to 

 the intestine and stomachs, and two branches to the liver. 

 Continuing upwards behind the liver, it sends off several 

 branches to the superior dilatation of the crop in the octo- 

 pus, and escaping from the dorsal cavity it divides into two 

 trunks, which encompass the oesophagus, like the two trunks 

 of the aorta in most cold-blooded vertebrata, or the first 

 branchial arch formed by the aorta in the embryos of higher 

 warm-blooded species. From this arterial oesophageal ring 

 two branches proceed upwards through the cranial aperture, 

 to supply the buccal apparatus and the upper pair of salivary 

 glands, and two larger branches, which pass downwards be- 

 hind the liver to ramify on the large inferior pair of salivary 

 glands and on the crop. The two trunks of the oesophageal 

 ring penetrate together the fore part of the cartilaginous 

 cranium, and then ascend, slightly diverging, to the bases of 

 the muscular arms, where each trunk divides into four 

 branches, like four branchial arches, which accompany the 

 brachial nerves, ramifying symmetrically along the central 

 cavities of the eight arms. 



The smaller aorta arises from the anterior or ventral as- 

 pect of the heart, and immediately sends off two lateral 

 branches to supply the numerous glandular vesicles of the 

 great venous trunks. Another considerable branch from 

 this artery ramifies on the intestinal canal, and sends twigs 

 to the adjoining folds of the peritoneum ; but the principal 

 trunk continues its course forwards in front of the great vena 

 cava, and extending along the anterior connecting band of 

 the mantle, ramifies on the muscular parietes of that cavity. 

 The third arterial trunk originating from the heart, proceeds 

 from its inferior surface, and is directed backwards, to ramify 

 on the testis of the male or the ovarium of the female, and 

 varies in its development, as in other animals, according to 

 the periodical changes in the condition of these organs. 



The absence of valves at the origin of the branchial arte- 

 ries in the octopus* is compensated for by the greater muscu- 



