MYOLOGY OF THE CHEIEOPTEE A . 
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There is no obturator interims, except in Megaderma , in which a few fibres of the 
gemellus extend to the inner side of the obturator membrane. 
Gemellus exists, in Pteropus, Megaderma , and Vampyrops, as a band of fibres from 
the tuber iscliii to the trochanter above the obturator externus ; it is absent in the other 
genera. 
Rectus femoris (Plate XIV. fig. 13, d) has a single iliac head in Eleutherura, has two, 
as usual, in Noctulina, Yampyrops , Cephalotes, Macroglossus , Megaderma , in the last of 
which it is largest of all proportionally; it joins the rest of the extensor at the middle 
third of the thigh, and is inserted with it. 
Extensor cruris femoralis (crureeus, Plate XIV. fig. 13, e) is but a single band in all 
the Bats, which arises from the upper fourth of the femur, and joins the last to be 
inserted into the tubercle of the tibia ; the tendon crosses the knee, but has no patella 
in it. This muscle is largest in Megaderma , in which there is an obscure sign of a 
division. 
Semitendinosus (Plate XIV. fig. 14,/’) is the most posterior and internal of the two 
hamstrings ; it arises from the back of the tuber ischii, and is inserted separately below 
and behind the semimembranosus. In Cephalotes it is small, and has a caudal origin ; 
it has a long tendinous origin and a longer tendinous insertion in Megaderma. In 
Pteropus it has a caudal origin and is penniform ; but in none does it present the curious 
inscription found in the higher Primates. 
Semimembranosus (Plate XIV. fig. 14, g) in Noctulina is once and a third larger than 
the last-named ; its insertion is above and in front of the last ; its origin is also ischiatic, 
and it is larger than the last in Cephalotes and Eleutherura. In Rhinolophus these 
two muscles, though double at origin, have only a single insertion ; and in Megaderma 
the semimembranosus is either absent or fused with the gracilis. In Pteropus its inser- 
tion is slightly joined to that of the gracilis, and its origin is purely ischiatic. 
The leg-muscles are in the smaller Bats exceedingly small and difficult to be separated ; 
the flexor aspect is directed forwards, and there is no trace of popliteus, soleus, or plantaris 
in any, with one exception, viz. on the back of the knee in V ampyrops I found a few 
oblique fibres like a rudimental popliteus (Plate XIV. fig. 17, h). Meckel says there is 
a soleus, but this is an obvious mistake. The gastrocnemius is a very delicate muscle 
with two heads, except in Megaderma (which has only an inner head) ; these are from 
either condyle, and the external head, or that from the tibial condyle, has a sesamoid 
bone (Plate XIV. fig. 16, c) in most species except Noctulina. This muscle lies at the 
inner part of the leg, has a long tendon, and ends in the os calcis. 
The digital flexors are two in number as usual. The flexor digitorum longus arises 
from the upper part of the back of the tibia ; it passes down the outside of the leg, and 
is crossed by the tendon of the tibialis posticus ; having passed the os calcis, it is joined 
by the next muscle : it is small in Cephalotes , still smaller in Megaderma , largest in 
Eleutherura. 
Flexor hallucis longus arises from the fibula for its whole length, and from the slender 
MDCCCLXXII. Y 
