FROG. 97 



Make an outline sketch of the dorsal aspect of the 

 frog, 



II. The Buccal Cavity. 



Open the mouth and note : 



1. Its wide cavity ; the posterior part, the 



pharynx, is continuous with the oesoph- 

 agus. 



2. The teeth : 



(a) On the upper jaw. 



(b) On the roof of the mouth. 



3. The posterior nares. 



To find them, pass bristles into the anterior 

 nares and note the points of entrance into 

 the mouth-cavity. 



4. The Eustachian recesses : a pair of lateral pro- 



longations of the mouth-cavity. Pass a 

 bristle through the tympanum from the 

 outside and note the place of its entrance 

 into the mouth- cavity. 



5. The tongue. Note its shape and its attach- 



ment. Turn it forward to see : 



6. The glottis : a longitudinal slit in the floor of 



the mouth. 

 Pass a probe into it. 



III. The Abdominal Viscera. 



Lay the frog iipon its hack in a pan containing 

 wax, and fasten it down with pins through the 

 limbs. Cut through the skin along the median 

 ventral line, and make a transverse cut at 



