402 Royal Society : — 



PROCEEDINGS OF LEARNED SOCIETIES. 



EOYAL SOCIETY. 



January 11, 1872. — George Biddell Airy, C.B., President, 

 in the Chair. 



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

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



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 (Galeopithecus). The species of Bats examined 

 were the following : — Pteropus edulis, medius, Edivardsii, Macro- 

 glossus minimus, Cephalotes Pallasii, Cynonycteris amplexicaudalis, 

 Eleutherura marginata, Rki?iolophus ferruyn-equinum, speoris, and 

 diadema, Megaderma lyra, Arctibeus jamaicensis, Vampyrops vit- 

 tatus, V espertilio murinus, Vesperugo pipistrellus, Synotus barbas- 

 tetlus, Plecotus auritus, Noctulina altivolans, and Scotophilus hes- 

 perus. 



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 fol- 

 lows : — 



1st. The singularly modified occipital trapezius. 



2nd. The enormously developed and subdivided great pectoral. 



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

 ing 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 conse- 

 quent on the rotation of the lower limbs backward — such as the 

 everted iliacus, the diminished glutei, and the weakness of the ex- 

 tensors 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 

 rudimental popliteus in another. 



The cutaneous muscles are of very great interest ; and this is in- 

 creased 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 identifi- 

 cation of some disputed muscles. Thus he has shown that the 

 upper part at least of the occipito-poUicalis is of the nature of the 

 trapezius, although its continuation is a cutaneous muscle ; and 

 this is interesting, as in the other flying mammals the entire of this 



