MYOLOGY OF THE CHEIKOPTEKA. 
141 
into the clavicle at its outer fourth, behind the cervical trapezius when that muscle 
exists ; in the Pipistrelle it arises from the fourth alone ; in Pteropus its fibres run to 
the outer point of trisection of the clavicle. It is very strong in Cephalotes, and sends 
some fibres to the acromion. 
Muscles of the Upper Extremity. 
The deltoid is divided into three parts in general, which look like perfectly separate 
muscles ; the acromial deltoid (Plate XIII. figs. 9, c, 10, a) is very distinct, arising from 
the acromion process of the scapula, and inserted into the upper and outer part of the 
humerus on the outer side of the pectoral ridge. In Macroglossus and Pteropus it 
extends below the pectoral muscle (the same length in Pt. Edwardsii, twice as far down 
in Pt. edulis , Humphry). I could not find in any of the species of Pteropus , Eleutherura , 
Cephalotes , or Macroglossus any of the posterior fibres running into the triceps ; they 
are closely applied together, and without careful dissection cannot be separated. In 
Plecotus this muscle is solid and thick, and its insertion is high up ; the opposite extreme 
in the way of length is in Eleutherura , in which the muscle extends for one sixth of the 
humerus below the inferior border of the insertion of the great pectoral. In Vampyrops 
the fibres run from the acromion in a radiating manner, the upper being short and 
nearly transverse, the lowest being long and oblique. In Megaderma its origin extends 
behind the acromion from the meso-scapula, and its fibres take the same course as in 
Vampyrops ; thus its fibres have the same relation to the clavicular deltoid that the 
scapular deltoid has to it. 
The clavicular deltoid is in general, as Meckel describes, inseparable from the great 
pectoral, and is not absent as Cuvier supposed ; it is always separate from the acromial 
portion : the muscle is partly separated from the pars sternalis of the pectoral in Eleu- 
therura. , completely separated in Megaderma and Pteropus edulis, arising from the outer 
fifth of the clavicle (outer half in Pt. edulis)', it is inserted over the pectoralis major, 
and the borders of the muscles are superficially marked out from each other by a vein 
(the cephalic). In Pteropus Edwardsii , Humphry found the deltoid attached to the 
outer half of the clavicle, internal to the insertion of the trapezius ; he also found it 
blended with the pectoralis major at its insertion ( loc . cit. p. 305). It is always with 
the pars sternalis of the pectoral that the clavicular deltoid is fused, not with the pars 
clavicularis, which lies on a plane deeper. 
The scapular deltoid (Plate XIII. figs. 9, g, & 10, d) is nearly inseparable from the 
acromial in Phinolophus diadema, at least the contiguous fibres are nearly parallel 
and closely applied to each other. In general this muscle arises from the margins of the 
infraspinous fossa, over the infraspinatus muscle, from which it is separated by a thin 
layer of fascia. In Macroglossus it is attached to the posterior half of the lower margin 
of the scapular spine, as well as to the posterior margin of the postscapula. In Eleu- 
therura its fibres are very transverse, chiefly from the hinder margin, and on the same 
plane with those of the teres major. In the Pipistrelle its outer and upper fibres are 
mdccclxxii. u 
