THE FROG 29 



The submucosa. Along its inner margin, adjacent 

 to the mucosa, observe a narrow zone called the muscularis 

 mucosas, consisting of an inner circular and an outer longi- 

 tudinal layer of non-striated muscle fibers. (In the intestine 

 a muscularis mucosse is sometimes found, but never well 

 developed.) 



(c) The muscular layers. Compare with those of the 

 small intestine. The longitudinal muscle layer is almost en- 

 tirely absent, its place being taken by connective tissue. 



(d) The peritoneum, as in sections of the intestine. 

 Study carefully one of the gastric glands of the mucosa; 



note three regions distinguished by the different character 

 of the cells. The three regions may be called mouth, neck 

 and body respectively. Under high power, draw a gland 

 showing clearly the character of the cells in the different 

 parts; the drawing should be about 8 or 10 centimeters in 

 length. 



VI. THE UROGENITAL SYSTEM. 



A. General Anatomy.- -Review your observations on 

 the excretory and reproductive systems (urogenital sys- 

 tem) of both sexes, supplementing the study of your own 

 specimen by the examination of permanent preparations. 

 Make an outline sketch of the urogenital system of your own 

 frog, including in your drawing the large intestine and the 

 cloaca in order to show the connection of the ducts and the 

 bladder with the cloaca. If the specimen is a female it may 

 be necessary to remove the ovary of one side, if this has not 

 already been done, in order to expose the kidneys and ure- 

 ters ; this ovary may be omitted from the drawing. On ac- 

 count of their intimate relation to the reproductive system, 



