18 GENERAL ANATOMY OF THE FROG. 



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

 with thick white walls, lying at the sides of the body 

 cavity. 

 8. 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 Fig. 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. 



E. The Digestive Organs. 



Fis. 3. General view of the viscera of the male frog, from the right side. 

 a, stomach : h, bladder : c, small intestine : d, cloacal aperture : 

 d, large intestine : e, liver : /, bile duct : g, gall bladder : /i, spleen : ?, lung : 

 A-, larynx : I, fat body : m, testis : n, ureter : o, kidney : p, pancreas : 

 r, pelvic symphysis : .s, cerebral hemisphere : sp, spinal cord : <, tongue : 

 u, auricle : 7/r, urostyle : v, ventricle : v.s, vesicula seminalis : ?/;, optic 

 lobe : a:, cerelDellum : y, Eustachian recess : z, nasal sac. 



