16. MIKIOPTERUS. 349 



Thumb moderate ; terminal phalanx of longest finger flexed 

 forwards, in repose, on the under surface of the metacarpal, reaching 

 as far as the junction of the proximal and middle thirds of that 

 bone ; wings to the ankles, or to the extremity of the tibise ; feet 

 long and slender, the outer toe (corresponding to the hallux, or 

 inner toe, in other five-toed mammals) nearly on a level with the 

 extremities of the other toes ; tail slightly longer than the head and 

 body, ivJiolly contained within the interfemoral membrane ; no post- 

 calcaneal lobe. 



The face in front of the eyes is covered with short fur inter- 

 spersed with longer hairs arising from the glandidar prominences on 

 the sides of the muzzle ; on the wing-membrane the far extends as 

 far as a line drawn from the end of the proximal third of the 

 humerus to the middle of the femur, and upon the interfemoral to a 

 very small extent, about as far as the end of the first caudal 

 vertebra. Beneath, the wing-membrane is clothed as far as a line 

 drawn from the middle of the humerus to the knee ; the inter- 

 femoral has a few long hairs about the root of the tail, but about 

 half the surface of the membrane is covered with a very fine pubes- 

 cence ; a band of fine short hairs passes outwards on the wing- 

 membrane behind the forearm to the carpus. 



The colour of the fur varies very considerably. In European 

 specimens it is generally light greyish all over, or sometimes reddish, 

 the basal half of the hairs dark greyish brown. In specimens from 

 Northern Africa, inhabiting dry sandy regions, the fur is light grey 

 all over, while those from South Africa are much darker, the 

 extremities of the hairs generally reddish grey. In the European 

 and North-African specimens with pale fur, the ears and inter- 

 femoral membrane are white and the integument generally of a pale 

 whitish colour, the wing-membranes light greyish brown. In the 

 darker-coloured specimens, especially in those from South Africa, 

 the ears and integuments are dark brown. 



The inner upper incisor, on each side, is but slightly longer than 

 the outer incisor, and slants inwards and forwards, on its outer side 

 near the base a small blunt cusp ; the outer incisor unicuspidate, 

 blunt, and slanting less inwards than the inner one. Canines 

 moderately long and straight, with a horizontal slightly raised 

 cingulum, without a second cusp or basal projection. Pirst upper 

 premolar unicuspidate, with a small narrow acutely pointed cusp 

 and a broad cingulum, more developed posteriorly, touching the 

 cingulum of the second premolar, which is also horizontally ex- 

 panded, but in an anterior direction ; a wide space is thus caused 

 between the summits of the canine and second premolar, and the 

 extremity of the first premolar is much closer to the canine than to 

 the second premolar; the whole tooth is also slightly pushed 

 inwards. The last molar is somewhat more than half the antero- 

 posterior diameter of the second premolar. In the lower jaw the 

 four front incisors are nearly equal in size and are trilobed, those 

 next the canines larger, with rounded summits, and a single furrow 

 on the inner side cutting off a low blant cusp. The cingulum of the 



