xi PRACTICAL DIRECTIONS 545 



the xiphisternum to the pelvic symphysis, so as to open up the 

 abdominal cavity. From the anterior extremity of the incision make 

 transverse cuts, and turn back the flaps of muscle. 1 Note : 



1. a, The peritoneum ; b, the diaphragm , with its muscles and 

 central tendon ; c , the pink lungs, seen through the latter : make a 

 small aperture in the diaphragm on one side of the median line and 

 note the collapse of the corresponding lung. 



2. a, The liver, stomach, small intestine, cczcum, colon, and rectum 

 (pp. 512-516) ; b, the urinary bladder ; c, the scrotal sacs in the male ; 

 and by turning aside the intestines </, the kidneys ; and e, the ovaries 

 and oviducts (varying much in size according to age) in the female. 



3. a, The characters and relations of the lobes of the liver (compare 

 Fig. 137), and the folds of peritoneum which attach the liver to the 

 diaphragm ; b, the gall-bladder ; -e, the gullet, and its entrance into -f, 

 the stomach (note its cardiac and pyloric portions) ; g, the spleen. 



4. a, The parietal and visceral layers of the peritoneum and the 

 various subdivisions of the mesentery ; b, the U-shaped duodenum, 

 passing into the ileum, and the connection of the latter with the 

 proximal end of c, the catcum, at the distal end of which is the 

 vermiform appendix, while proximally it passes into d, the colon, 

 continuous with e, the rectum, which enters the pelvic cavity to open by 

 the anus. 



II. Turn over the stomach to the animal's right side and make 

 out 



1. a, The postcaval vein, passing from the pelvis forwards, near the 

 ventral surface of the backbone, through a notch in the liver to the 

 diaphragm; b, \hedorsalaorta, running partly above, partly alongside, the 

 postcaval ; c, the cceliac artery, given off from the aorta about an inch 

 posteriorly to the diaphragm trace its main branches ; d, the anterior 

 mesenteric artery, arising about half an inch further back than the 

 coaliac trace its main branches (Fig. 137). 



2. a, The left kidney, with its artery, vein, and ureter ; b, the 

 yellowish left adrenal, anterior to the origin of the renal artery and 

 vein ; c, the left ovary, Fallopian tube, and uterus in the female. 



1 You will very probably notice a number of transparent, rounded 

 vesicles, about inch in diameter, in the abdomen. These are tape- 

 worms (phylum Platyhelminthes, p. 412) in the encysted stage, which 

 develop into the adult form when swallowed by a dog. 



PRACT. ZOOL. N N 



