16 GENERAL ANATOMY OF THE FROG. 
b, The tongue: thin and fleshy: attached to the front 
part of the floor of the mouth, and with its free 
bilobed end turned backwards toward the throat. 
Turn the tongue forward with the forceps to see :-— 
c. The glottis: a longitudinal slit in the floor of the 
posterior part of the mouth: its sides are stiffened by 
the arytenoid cartilages. 
Pass bristles through the glottis into the lungs. 
C. The Abdominal Viscera. 
Lay the frog on tts back under water, and fasten it down to the 
dissecting board by pins through the limbs. Cut through the skin 
along the middle line the whole length of the ventral surface. 
Separate the skin from the underlying parts, noticing its very loose 
attachment to these parts, and the large space—lymph cavity— 
beneath it. Turn the flaps of skin outwards and pin them back. 
Notice -— 
a. The muscles forming the body wall. 
6. The sternum, or “ breast-bone,” in the middle line, 
opposite the fore-limbs. 
Pinch up with forceps the muscular body wall, and cut through 
at into the body cavity with scissors a little to the right of the 
median line, being careful not to injure the anterior abdominal 
vein which runs along the inner surface of the body wall wm the 
middle line. 
Continue the cut backwards to the hinder end of the body and 
forwards to the jaw, cutting through the sternum with strong 
scissors, and taking care not to injure the parts beneath. 
Note on the inner surface of the left flap the anterior abdominal 
vein, and carefully dissect this from the flap. Pull the two flaps 
apart, cutting through them transversely at their posterior ends to 
facilitate the process, and pin them out so as to display the viscera. 
Inflate the lungs with a blowpipe through the glottis, and inflate 
the bladder through the cloacal aperture. 
Note and draw the generat arrangement of the viscera, 
showing :-— 
1. The heart: enclosed in the pericardium: situated in the 
middle line in front, and in the natural condition of the parts - 
covered by the sternum 
