164 VERTEBRATES 



External Form. — (i) In the chloroformed specimen 

 notice the general shape of the body and compare it with 

 that of the fish and insect. 



Observe the divisions of the body into head, thorax and 

 limbs; with the fingers try to determine where the bones 

 are and thus trace the main features of the skeleton. Has 

 it a tailf Describe briefly the general plan of the framework. 



(2) Study the head. Note the appearance of the dor- 

 sal side of the head. Find the nostrils, anterior nares; 

 note their lining, color and size. Find the ears, tympanic 

 membranes ; study their size, shape and markings. Be- 

 tween and below the eyes, find a round spot, the brow spot 

 or pineal eye. Note its location between the eyes and the 

 nose. Look carefully for eyelids. Do you find the external 

 parts of the eye similar to those of the fish? Draw the 

 posterior of the head (X2). 



1,3) Open the mouth as wide as possible; study the 

 tongue, noting its size, shape in front and back, its point 

 of attachment and the freedom of motion possible to it. 

 What use is made of this free motion of the tongue? Is 

 there anything else about the tongue that will help in catch- 

 ing prey ? 



Remove the tongue and study its surface. Do you find 

 papillae or taste bulbs? Does there seem to be a regularity 

 about the furrows? Observe the upper part or roof of the 

 mouth. Do you find a soft palate, the tonsils? Describe 

 what you find and compare the tongue and roof with like 

 parts of the mouth of the fish. Draw the tongue from the 

 top (X3) and make a diagrammatic section from the side 

 showing its attachments to the bottom. Study the jazvs; 

 note shape, size and movement. Do you find teeth in both 



