THE BATS 



81 



Tragus. 



A. Human Ear for 

 comparison. 



All bats are mainly nocturnal in habits. They never produce 

 more than two, and usually only one, young 

 at a birth. They only seem to breed once in 

 the year, in the spring-time. The period 

 of gestation probably varies in the insecti- 

 vorous bats from three months to a month 

 and a half. The young at parturition are 

 of fairly large size, but are blind and naked. 

 As they emerge from the body of the mother 

 they are received into a bag formed by the 

 forward- curled tail and its membrane on 

 either side. Thence, after being licked over 

 and cleaned by the mother, they are hoisted 

 up by the fingers of the wing to the mother's 

 breast. Here 

 they cling 

 tightly with 

 their own wing 

 membranes, 

 thumbs, and 

 hind feet, 

 thus spreading 

 them s elves 

 across the chest 

 of the mother 

 and fastening 

 on to one of 

 the nipples. 

 Some little 

 time after birth 

 the mother 

 constantly 

 guards the 

 young from 



observation by folding one wing over the body, suspending 

 herself by the thumb of the other. 



6 



Antltragus. 



B. Ears of Pteropodid and Rhinolophid Bats, without tragus. 

 a. Pteropus. b. Cynonycteris (PterotiodidcE). c. Rhinolophus. 



f 



C. Ears of Vespertilionid and Nycterid Bats, with tragus. 

 d. Megaderma (Nycteridce). e. Pterygistes noctula. f. Myotis bechsteini. 



EARS OF BATS, TO SHOW TRAGUS, ABSENCE OF TRAGUS, AND 



DEVELOPMENT OF ANTITRAGUS. (The three lower examples 



much enlarged.) 



