MYOLOGY OF THE CHEIROPTERA.. 
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middle third, in Pteropus and Macroglossus to the inner half, in Bhinolophus diadema, 
speoris , and ferrum-equinum to the outer half or third ; it is very small in the Megaderma : 
the fibres pass outwards from this origin, extend along the free edge of the propa- 
tagium to be inserted into the base of the terminal phalanx of the pollex. The muscular 
fibres are deeper in colour than those of the rest of the platysma, and vary in the 
different species in the distance to which they extend. In Vespertilio murinus , Synotus 
barbastellus , Macroglossus, and Plecotus they continue for two thirds the length of the 
entire course ; in the Phyllostomine Bats and Pteropus nearly one half is muscular ; in 
all the muscle ends in a highly elastic cord, which continues on nearly to the insertion. 
A short distance above the thumb, a few muscular fibres are superadded to this. Pro- 
fessor Humphry found in his specimen of Pteropus Edwardsii that the whole cord 
resolved itself into a second fleshy belly ; in Cynonycteris it had a large inferior fleshy 
belly ; in Pteropus edulis its origin was under cover of the nuchopatagial muscle. 
In all, immediately on the cessation of the secondary muscular fibres, the cord ceases to 
be elastic and becomes an ordinary tendon. 
At its commencement in Cephalotes this muscle receives a few fibres from the occi- 
pito-frontalis, and on the left side of the specimen dissected a muscular band from this 
muscle passed to the back of the concha auriculae (Plate XV. fig. 2, e). In the Eleuthe- 
rura this muscle and the occipito-frontal are even more closely connected. In Bliino- 
loplms diadema the muscle arises under cover of the retrahens aurem, and its fleshy fibres 
do not continue beyond the shoulder. At first the glandular and fatty masses asso- 
ciated with the thymus separate it from the cervical trapezius and from the platysma. 
Its fibres are perfectly free from those of any muscle at first, until it reaches the middle 
of the shoulder, where the superior middle and inferior parts of the platysma are inserted 
into it. The nature of this muscle has been the subject of difference of opinion. 
Professor Kolenati figures it as a special muscle under the name which I have adopted 
(Sitzungsberichte der Koniglich. bohmischen Gesellschaft der Wissenschaft, 1847, and 
the Allgemeine deutsche naturhist. Zeitung, Dresden, iii. Band, 1 Heft, p. 9, 1857); 
he also calls it extensor propatagii, or Hinterhaupts-Daumenmuskel. Cuvier and 
Laurillard figure it as the dorso-occipitien, and Humphry describes it as the second 
piece of the platysma. Cuvier (see Humphry, p. 304) supposes it might possibly 
be a modified part of the trapezius; and Meckel, in criticising Cuvier’s description 
of the trapezius in Bats, says, “ mais il existe en outre un muscle longitudinal qui est 
tout-a-fait separe du trapezius par le thymus, ce muscle prend naissance a la Crete occi- 
pitale, se porte en bas et en dehors a l’apophyse acromien et au grand pectoral avec 
lequel il s’unit anterieurement. Cette disposition est la premiere trace d’une faible 
separation de la partie anterieure du trapeze” (Traite d’Anat. Comp, traduit par 
Riester et Sanson, vol. vi. p. 219). Meckel’s failure in the tracing of this muscle he 
redeems subsequently in speaking of the muscles of the pollex ; it is plain, however, that 
in both places he is speaking of different aspects of the same muscle. 
I think we have sufficient reason to coincide with the theory thus proposed bb Meckel, 
