94 Prof. A. Macalister on the Myology of Cheiroptera. [Jan. If, 



II. "The Myology of the Cheiroptera." By A. Macalister, A;B., 

 M.B.T^C.D., Professor of Zoology, University of Dublin. Com- 

 municated by Dr. Sharpey, Sec. R.S. Received October 19, 1871. 



(Abstract.) 



This paper is a record of the structural details of nineteen species of 

 Bats, and for purposes of comparison the author has appended a description 

 of the muscles of the Flying Squirrel (Pteromys) and of the Flying Lemur 

 (Gateopithecus). The species of Bats examined were the following: — 

 Pteropus edulis, medius, Fdwardsii, Macroglossus minimus, Cephalotes 

 Pallasii, Cynonycteris amplexicaudalis, Eleutherura ?naryinata, Rhino- 

 tophus ferrum-equinum, speoris, and diadema, Megaderma lyra, Artibeus 

 jamaicensis, Vampyrops vittatus, Vespertilio murinus, Vesperugo pipis- 

 trellus, Synotus barbastellus, Plecotus auritus, Noctulina altivolans, and 

 Scotophilus hesperus. 



As the habits of the Bats are singularly different from those of the other 

 mammals, the study of their myology becomes a matter of great interest ; 

 the special features displayed by their muscles are very numerous, but the 

 principal of these may be tabulated as follows : — 



1st. The singularly modified occipital trapezius. 



2nd. The enormously developed and subdivided great pectoral. 



3rd. The digastric being intersected by a linear inscription, forming a 

 connecting link between the mammals with a single-bellied depressor of 

 the mandible and those with a biventral muscle. 



4th, The separate and displaced scapular deltoid. 



5th. The palmaris longus acting as a superficial flexor. 



6th. The displacements of the lower-extremity muscles consequent on 

 the rotation of the lower limbs backward — such as the everted iliacus, the 

 diminished glutei, and the weakness of the extensors of the knee. 



7th. The increased size of the gracilis. 



8th. The absence in general of the sartorius, tensor vaginae femoris, 

 biceps, plantaris, popliteus, and soleus. 



It is interesting, in connexion with this last peculiarity, to notice the 

 occurrence of a rudimental sartorius in one species and of a ruclimental 

 popliteus in another. 



The cutaneous muscles are of very great interest, and this is increased by 

 the comparison with those of the other flying mammals. 



The author regards it as a point of very great importance that he has- 

 been able to apply the test of nerve-supply in the identification of some 

 disputed muscles. Thus he has shown that the upper part at least of 

 the occipito-pollicalis is of the nature of the trapezius, although its con- 

 tinuation is a cutaneous muscle ; and this is interesting, as in the other 

 flying mammals the entire of this muscle is cutaneous and springs from 



