18 ELEMENTS OF MAMMALIAN ANATOMY. 
17. What is the ultimate syllable of all family names? 
18. Explain what is meant by binomial nomenclature. 
19. Name three families of Carnivora. 
20, Examine specimens and determine wherein the teeth of Canidz 
differ from those of Felide. 
21. What two rank names constitute the scientific name of an animal? 
22. Give the scientific name of five Carnivora, two Ungulata, and 
two Primates. 
23. Define organ, system, tissue, and cell. 
24. Name two organs belonging to each system. 
25. How do the elements of the four kinds of tissue differ? 
EXTERNAL FEATURES. 
The cat, like all other mammals, possesses two well- 
defined skeletons, the endoskeleton, consisting of the true 
bones, and the exoskeleton, composed of the skin and its 
appendages. The skin invests the body completely and is 
continuous with the lining of the digestive and urogenital 
canals. It varies in thickness in different regions, being 
very thin on the lips, ears, and eyelids, and exceedingly 
thick on the pads of the feet and on the ventral neck region, 
where, in contest with an enemy, it is most likely to be 
seized. A fibrous connective tissue binds the skin to the 
subjacent structures. In some places the union is very 
firm, as on the distal parts of the limbs and the head, while 
in other regions it is loose, as on the lateral aspect of the 
trunk. 
The skin consists of an external layer, the cpidermus, and 
beneath this, the dermus or true skin, designated the cori. 
The epidermis is composed of numerous strata of epithelial 
cells. Those on or near the surface are much flattened 
while the deeper ones are more or less cubical. As the 
superficial layer desquamates in minute fragments, forming 
what is commonly called dandruff, it is replaced by cells 
developed from the deeper layers. 
At the orifices of the internal passages, such as the diges- 
