20 



GENERAL ANATOMY OF THE EEOG 



b. The oviducts : two long, very much convoluted tubes with 

 thick white walls, lying at the sides of the body cavity. 

 7. In the male frog note, 



a. The testes : a pair of ovoid bodies of a pale yellow 

 colour, attached to the dorsal wall of the body cavity. 



D. The Peritoneum. 



Notice the thin pigmented membrane — the peritoneum — 

 which lines the body cavity. Trace this to the mid-dorsal line, 

 where it is reflected downwards as a double layer — the mesen- 

 tery — ^which embraces at its edge the alimentary canal, and 

 binds its several coils together. (See Eig. 2.) 



Notice also that all the abdominal viscera are really outside 

 the peritoneum, which forms a closed sac into which the viscera 

 are as it were pushed from without. 



The Digestive Organs. 



Fig. 3.— General view of the viscera of the male frog, from the 

 right side. 



a, stomach ; b, bladder ; c, small intestine ; cl, cloacal aperture ; 

 d, large intestine ; e, liver ; /, bile duct ; g, gall bladder ; h, spleen ; 

 i, lung ; k, larynx ; /, fat body ; m, testis ; n, ureter ; o, kidney ; 

 p. pancreas ; r, pelvic symphysis ; j. ceiebral hemisphere ; sp, spinal 

 cord; t, tongue; u, auricle; ur, urostyle ; v, ventricle; v.s, visicula 

 semmalis ; w, optic lobe ; x, cerebellum ; y. Eustachian 

 z, nasal sac. 



recess ; 



