6 LABORATORY STUDIES IN ZOOLOGY 



Ventral, i)crtaining to the venter. 



Cephalon, head, or that end which is foremost in locomotion. 



Cephalic, pertaining to the liead or foremost end. 



Cephalad, toward the head or foremost end. 



Caudal, pertainhig to the tail or hindermost end. 



Caudad, toward the tail or hindermost end. 



Meson, the imaginary plane in the exact middle of the hodj- dividing it 

 into a right and left half. 



Mesal, pertaining to the middle or mesal plane of the body, 



Mesad, toward or in the direction of the meson. 



Lateral, on either side of the meson. 



Laterad, extending from the meson toward either side. 



Ectal, i)ertaining to the surface of the body. 



Ectad, from the inner mass of the body toward or in the direction of the 

 surface. 



Ental, pertaining to the interior of the body. 



Entad, toward or extending toward the inner mass. 



Proximad, toward the proximal or fixed end of an organ {e.g., the shoulder 

 is at tlie proximal end of the arm). 



Distal, pertaining to the free end of an organ; {e.g., the hand is at the 

 distal end of the arm). 



Distad, toward the free end. 



Memorizing these terms as a set task is not advised. It is 

 better to refer to the table when necessary to know the meaning 

 of a term, thus learning it and its application at the same time. 



It is to be emphasized that the frog is studied as a representa- 

 tive animal to illustrate the fundamentals of organization upon 

 which our conception of an organism is based and the general 

 principles of biology in their application to animal study. It is 

 also studied to reveal the nature and architectural plan of a higher 

 animal. 



The study of the frog is enhanced by observations upon living 

 specimens, several of which should be available in the laboratory. 



Animals are noticeably different from plants in respect to the 

 necessity of voluntarily approaching the food which they appro- 

 priate from the world about them. 



Animals are rarely passively supplied with food. It is neces- 

 sary for them to forage, hence the need of organs of locomotion. 

 It is also necessary that the animal be in possession of some special 

 means of gathering information concerning objects and forces 

 about it in order that it may harmoniously adjust itself to these 

 environmental conditions. The manner in which these and other 

 similar problems have been solved in the animal body may be taken 

 as an expression of the object in studying the exterior of the frog. 



