16 GENERAL ANATOMY OF THE FROG. 



b. The tongue, which is thin and fleshy, is attached to 

 the front part of the floor of the mouth, and has its 

 free bilobed end turned backwards towards the throats 



Turn the tongue forwards with the forceps. 



C. The glottis, or aperture of the larynx, is a longitudinal 

 sht in the floor of the posterior part of the mouth 

 stiffened laterally by the arytenoid cartilages. 



Pass bristles through the glottis into the lungs. If 

 any difficulty is experienced in finding the glottis 

 snip through the angles of the mouth ivith scissors, 

 so as to allow the mouth to he opened more widely. 



C. The Abdominal Viscera. 



Lay the frog on its hack under ivater, and fasten it doimi to the 

 dissecting hoard hy pins through the limhs. Cut through the skin, 

 along the middle line, the ivhole length of the ventral surface. 

 Separate the shin from the underlying parts, noticing its very loose 

 attachment to these parts, and the large space — lymph cavity — 

 heneath it. Turn the flaps of skin outwards and pin them hack. 

 Notice : — 



a. The muscles of the body w^all. 



b. The pectoral or shoulder girdle : a bony arch running 



across the body, opj)Osite the fore-limbs. 



Pinch up with forceps the muscular hody wall, and cut through 

 it into the hody cavity with scissors a little to one side of the 

 median plane, heing careful not to injure the anterior abdominal 

 vein which runs along the inner surface of the hody wall in the 

 middle line. 



Continue the cut backwards, to the hinder end of the hody, and 

 forwards to the jaw, cutting through the pectoral girdle ivith strong 

 scissors, a?id taking care 7iot to injure the parts heneath. 



Note on the inner surface of the larger flap the anterior abdominal 

 vein, and carefully dissect this from the flap. Pull the two flaps 

 a^mrt, cutting through them transversely at their posterior ends to 

 facilitate the process, and turn them hack so as to display the viscera. 



Inflate the lungs with a blow-pipe through the glottis, and 

 inflate the bladder through the cloacal aj^erture. 



Note and draw the general arrangement of the viscera, showing 

 the following structures : 



