13- 



October, 11, 1831. 

 Joseph Cox Cox, Esq. in the Chair. 



At the request of the Chairman Mr. Martin read the following 

 notes of some particulars observed on the dissection of a Monitor, 

 which died a short time since at the Society's Gardens. They were 

 illustrated by a drawing, in which was represented the distribution 

 of the principal blood-vessels. 



" Proceeding from the ventricle by a trunk which appears single, 

 but which in reality is divided internally, five arteries are seen, 

 which may be characterized as two aortce, two pulmonary, and one 

 cervical. 



" The cervical runs between, and somewhat anterior to, the two 

 aortce, and, continuing single for upwards of three inches, divides 

 into two branches at the root of the neck, under the arch formed 

 by the scapulce ; these two branches pass along on each side of the 

 neck, a short distance from the oesophagus. 



" The right aorta proceeds upwards for about an inch and a half, 

 and then suddenly turns round the right bronchial tube of the larynx, 

 as that tube is about to enter the lungs by two subdivisions, the 

 superior of which is reflected up like a hook, to link with the artery 

 turning round it, the inferior passing downwards. Having made 

 this turn the artery proceeds downwards, but at half an inch from 

 its turn sends off a branch at a singularly acute angle, which runs 

 upwards just under the main cervical artery for about an inch, and 

 then divides into two, which running obliquely upwards pass one 

 on each side under the bronchial tubes, and then over the first rib 

 to the humerus; these are the subclavian arteries. It is to be ob- 

 served that before passing over the ribs they send off an artery to 

 the under surface of the scapula and muscles of the neck. The 

 right aorta having thus given off the subclavian, passes down behind 

 the heart, and just below this organ anastomoses with the left aorta, 

 which arising on the left of the cervical branch from the common 

 stem, turns over the bronchial division on the left, exactly as hap- 

 pens on the right side, only a little higher up, runs down behind 

 the heart, and after its anastomosis ends in two large branches, which 

 take their course along the mesentery; so that it maybe considered 

 as analogous to the mesenteric arteries. The true or right aorta, 

 taking a straight course onwards to the tail, gives oft" two branches 

 just below the anastomosis, one of which is the splenic, the other is 

 small, and goes to the mesentery; considerably lower another small 

 mesenteric artery is also given off. 



" The pulmonary arteries arise one on each side from the common 

 stem, and taking a short course upwards enter the lungs, subdi- 

 viding into several branches. 



u The blood from the upper parts of the body is brought to the 

 [No. XII.] Zool. Soc. Proceedings of the Comm. of Science. 



