FREE-TAILED GROUP. 297 



present in the males as well as the females, Dr. Dobson suggests that in cases where 



there are twins the male parent may relieve 



his mate of the task of carrying one of the 



offspring ; instances of a similar division of 



labour being believed to occur among the 



fruit-bats. 



This bat, which is figured in the illus- 

 tration on p. 246, occurs in the larger islands, 

 such as Java, Sumatra, and Borneo, of the 

 Malayan region, where it dwells in the 

 heart of the densest forests. During the 

 clay its place of repose may be either a 

 hollow tree, or a cleft in the rocks, or 

 even a hole in the ground. Its flight, 

 which is heavy and slow, commences as HEAD OF FEMALE OF THE NAKED BAT. After Dobson. 

 soon as the sun reaches the horizon, and 



takes place in the openings and glades of the forests, or even high up in the 

 air in the open plains. 



THE WRINKLED-LIPPED BATS. 

 Genus Nyctinomus. 



By far the most abundant in species of the bats of this group, as well as the 

 most widely spread, are the wrinkled-lipped bats of the warmer regions. While 

 closely allied to the mastiff-bats, they are distinguished by the upper incisor teeth 

 being separated from one another in the middle line, and also by the much greater 

 development of the vertical wrinkles on the capacious lips. The ears are generally 

 more or less extensively united together at their bases, and the number of teeth varies 

 from thirty-two to twenty-eight. One member of the genus, Ceston's bat 

 {Nyctinomus cestoni), is the solitary representative of the whole family found in 

 Europe, where it extends as far northwards as Switzerland. This species measures 

 nearly 3 J inches in length, exclusive of the tail, but most of the others are smaller. 

 Ceston's bat has the peculiar power of being able to sink its eye within the socket, 

 and then to protrude it again. It has, perhaps, the widest range of all the species, 

 occurring not only in the south of Europe, but also in Egypt, Nubia, Amoy, and China. 

 The late Mr. Swinhoe, writing of this species, observes : " I have often on a cloudless 

 evening, at Amoy, seen these bats flying along, high in the air, being easily distin- 

 guished by the narrowness of their wings. When watched, the creature has a habit 

 of exposing its tail, and of sinking its eye into the socket and thrusting it out again. 

 The membrane extending from the tail to the legs is wrinkled, and covers the tail 

 like a glove, so as to slip up and down as the creature wishes to expand or contract 

 its interfemoral wing, or, in nautical language, to shake out or take in reefs." The 

 tail cannot, however, be completely withdrawn into the membrane, in the manner 

 of the tomb-bats. 



Two species are found in India, two in Australia and New Guinea, and 



