CHAPTER I. 

 GENERAL ANATOMY OF THE FROG. 



Fig. I. — The Common Frog {Sana temforaria] (from Ecker). 



A. External Characters. 



Lay the frog on a hoard before you ; note, and tnake drawings 

 showing the folio uring points : 



1. The division into head, trunk, and limbs ; and the ab-sence 

 of neck and tail. 



2. The two great surfaces. 



a. The dorsal surface, or back, is directed upwards when 



the frog is in the natural position. 



b. The ventral surface, or belly, is directed downwards 



towards the ground. 



