256 COMMON BRTIISH ANIMALS 



Two kinds of camels are known to ns, the shaggy- 

 haired, two-hnmped Bactrian camel, which is able to 

 endure the severe cold of Central and Eastern Asia, 

 and is the main means of communication between 

 China, Tibet, and Kashmir, and the one-humped 

 camel or dromedary, the ''ship of the desert," which 

 is accustomed to a warm climate. The one-humped 

 camel is to the peoples of the dry and sultry deserts 

 what the reindeer is to the peoples of the icy north. 

 Both camels digest and thrive upon the poorest 

 food, and they have the power of storing water in 

 their stomachs for use when needed. There are but 

 three chambers to their stomachs, the second cham- 

 ber or reticulum being a mere vestige, but there 

 are in the walls of the rumen little pits with narrow 

 mouths. Around each mouth there is a band of 

 muscle called a sphincter muscle, which contracts 

 and closes the pit when it is filled with water and 

 relaxes when its contents are needed in the process 

 of digestion. These pits are called " water cells," 

 and are well filled by the camel whenever an oppor- 

 tunit}^ for drinking occurs. There are many extra- 

 ordinary adaptations to environment to be met with 

 in nature, but none perhaps more striking than this 

 adjustment of the internal economy of the camel to 

 the arid districts with which it is associated. 



Camels are restricted to the Old World. Their 

 representatives in the New World are the llamas of 

 South America. Of these there appear to be three 

 varieties, the llama, the alpaca, nnd the vicuna. 

 All produce hair and wool, which are extremely 

 useful in the manufacture of cloth. They were also 



