MYOLOGY OF THE CHEIROPTERA. 
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species, but only extends into the scaphoid and internal cuneiform in Megaderma and 
Macroglossus. 
Extensor hallucis longus exists as a separate muscle only in Macroglossus ; it is very 
slender, and passed from the interosseous border of the tibia to the hallux. I found no 
trace of it in any other species. 
The dorsum of the foot presented two muscles : — 
Extensor digitorum brevis, which in all was moderately strong and passed from the 
outer side of the tarsus to the four fibular toes. Separate from this in all was the 
extensor hallucis brevis, which arises from the lower end of the tibia and front of the 
tarsus, and is inserted into the great toe ; this is largest in Noctulina and Eleutherura. 
In the sole of the foot are the following muscles : — 
Levator ossis styliformis, a slender muscle from the back of the lower part of the ankle 
to the upper surface of the styliform bone. This muscle is small, and proportionally 
largest in Noctulina. 
Depressor ossis styliformis (styliform muscle of Humphry) starts from the plantar 
surface of the calcaneum ( Noctulina ), or from the fifth metatarsal bone ( Pteropus and 
its allies), to the lower border of the spur. 
Abductor minimi digiti, abductor ossis metatarsi minimi cligiti, and abductor hallucis 
were present in all, and displayed no features of particular interest. The flexor brevis 
digitorum in all divided into four slender bellies, whose tendons supplied the four digits 
on the fibular side ; it was small in Pterojms , larger in Macroglossus. There were eight 
lumbricales : one of these arose from the flexor hallucis tendon, and supplied the inner 
side of the great toe ; one arose from the flexor digitorum longus tendon, and supplied 
the fifth toe on its tibial side ; and for each of the other toes there were two, one from 
the flexor hallucis tendon, and one from the flexor digitorum longus. 
The transversalis pedis was very large and double in Macroglossus, single and large 
in the others ; in Pteropus it was very wide, and stretched from the fifth metatarsal bone 
and from the first phalanx of this digit, from the fourth and partly from the third meta- 
carpal bones, into the metacarpal bone and first phalanx of the hallux. Professor 
Humphry, in his description of this muscle, regards its halluceal attachment as its origin, 
and its minimal attachment as insertion. 
There are ten single-headed interossei, one on each side of each digit. 
For purposes of comparison I have dissected two other types of so-called flying 
Mammals : one the Pteromys volans, or Flying Squirrel, of the order Podentia ; the 
other Galeopithecus volitans, or Flying Lemur, of the order Insectivora. As an appendix 
to the Myology of the Cheiroptera I shall briefly state the muscular peculiarities met 
with in these species. 
In Pteromys the cutaneous muscles were : — 1st. Carpo-tarsal (Plate XYI. fig. 1, _/'), a 
strong cord of muscular fibres extending in the margin of the plagiopatagium from the 
tip of the styliform bone of the carpus to the inner side of the tarsus, and more parti- 
y 2 
