544 ANNUAL EEPORT SMITHSONIAN INSTITUTION, 1917. 



building are most of the larger cats, the hyenas, the hippopotamuses, 

 and some tropical mammals. Here also are most of the reptiles. 

 Near by are the monkey house and the bird house, and to the north 

 the antelope house, elephant house, and zebra house. Outdoor yards 

 and cages are placed throughout the park in situations favorable to 

 the comfort and health of the various species exhibited. 



The interest of the public in the National Zoological Park is 

 attested by the number of visitors. In 1916 and in 1917 the attend- 

 ance was over 1,000,000 each year, with a daily average of over 

 3,000 visitors; and in 1918 a total number of 1,593,227 people were 

 admitted to the grounds, a daily average of 4,365. Although the 

 Sunday and holiday crowds are largely composed of residents of the 

 District of Columbia and near-by States, the week-day attendance is 

 in a large measure made up of visitors from the country at large. A 

 large share of the enormous number of tourists to Washington visit 

 the Zoo and the sight-seeing cars now regularly include the park in 

 their itineraries. Many people are attracted to the park on account 

 of its wallis and drives, and as the entire area is a carefully protected 

 sanctuary for wild birds and flowers many nature classes from the 

 schools visit it on their field excursions. 



The grounds and buildings are open each day in the year, and 

 admission is always without charge. 



MAMMALS. 



The mammals (class Mammalia) comprise those creatures com- 

 monly known as "animals." They are usually distinguishable from 

 other vertebrates by numerous well-known superficial characters and 

 are briefly defined technically as warm-blooded vertebrates with 

 hair,^ and with glands in the female for the secretion of milk for 

 the nourishment of the young. Mammals offer a great range of 

 variety in size, general appearance, and mode of life. The elephant, 

 whale, mouse, shrew, and bat include examples showing extremes 

 in bulk and habit. The vast majority of the mammals usually ex- 

 liibited in zoological gardens belong to the subdivisions of the 

 class known as the ungulates (hoofed mammals), primates (apes, 

 monkeys, and lemurs), rodents (gnawing mammals), carnivores, 

 (flesh-eaters), and marsupials (pouched mammals). In the National 

 Zoological Park good collections of numerous species of these groups 

 of mammals may be seen and studied to advantage. A few repre- 

 sentatives of another gToup, the Edentata, which includes the sloths, 

 anteaters, and armadillos, are also shown. 



^ " To define a mammal as a vertebrate with hair would be an entirely exclusive defi- 

 nition ; even in the smooth whales a few hairs at least are present, which may be reduced 

 to as few as two bristles on the lips" (Beddard). 



