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PROFESSOR A. MACALISTER ON THE 
present in all the species, and is large in Noctulina , Cephalotes , Megaderma , and Eleu- 
therwra : this muscle is always separate from the foregoing. 
4th. Flexor pollicis brevis ulnaris, from the os magnum to the ulnar side of the first 
phalanx, is also always present. 
5tli. An adductor pollicis is present in Macroglossus and Megaderma as a small trans- 
verse bundle from the second metacarpal to the base of the first phalanx of the pollex. 
For the little finger there are in nearly all Bats the following muscles : — 1st. Abductor 
from the unciform ; in Megaderma it arises from the palmar ossicle, and in Macroglossus 
and Ceplialotes from a thread of the tendon of the flexor carpi ulnaris ; it is inserted 
into the first phalanx of the little finger. 2nd. Opponens minimi digiti is very small 
and rudimental in Macroglossus , absent in most of the others, and existed in that species 
as a thin filament from the carpus to the metacarpal bone. 3rd. Flexor brevis minimi 
digiti is the radial interosseous muscle for this digit : its origin is peculiar ; it springs 
from the extremity of the transverse process of the os magnum, it lies superficial to the 
origins of the other interossei muscles and to the tendon of the flexor profundus 
digitorum et pollicis under cover of the palmaris longus, and it is inserted into each side 
of the second phalanx by a split tendon. 
For the index-finger there is an opponens, or a metacarpal flexor, in Noctulina ; there 
are in the others two interossei present. 
For the middle finger there are also two interossei; one of these in Macroglossus , as 
already described, arises from the flexor digitorum tendon, the other arises from the os 
magnum and trapezoidale. In Noctulina these two muscles are combined, but the 
tendon is double ; in the same species this muscle arises in common with the inter- 
osseous for the ring-finger, which is also single, as it is in all the species, but has a double 
tendon. There are no anconei muscles in the forearm, nor is there any palmaris brevis 
in the hand. The thumb-muscles are supplemented in their action by the occipito- 
pollicalis above described. 
Muscles of the Abdomen. 
Both in males and females the abdominal wall-muscles are very thin, and invested by 
a strong elastic layer of fascia, which lays immediately under the skin ; from this arises the 
pectoralis quartus, and under it is the external oblique, which arises from the five or six 
lower ribs, indigitating with the serratus magnus ; it soon becomes tendinous, and is 
inserted over the rectus into the linea alba ; its lower border forms a strong Poupart’s 
ligament. 
The internal oblique and transversalis combined form one inseparable muscle (except 
in Pteropus , in which they are for the upper half of the abdomen perfectly separable), 
which underlies the last, and passes behind the rectus. Its origin is from the lumbar 
fascia and ilium, and apparently from the lower margin of the lowest rib ; its insertion 
is into the linea alba ; none of its fibres go in front of the rectus. For the lower 
quarter of the abdomen these muscles are very thin and fascial in nature. Piercing its 
