1872.] Gr. E. Dobson — On the Osteology of some species of Bats. 335 



second phalanx by a perfect joint. This phalanx is scarcely ^ inch in 

 length, and is wholly contained within the wing membrane. 



If we compare the skull of JK. spelceus with that of Pteropus medius, 

 it will be found to resemble it very closely, differing from it only in size, 

 and in the following points : — 



In Ft. medius, the sagittal crest is very prominent, forming a sharp 

 ridge continued forwards beyond the middle of the zygomatic arches, 

 dividing at a short distance behind the post-orbital processes of the frontal 

 into two ridges which become continuous with their posterior margins. In 

 M. spelceus, the sagittal crest is very short, dividing, at a point correspond- 

 ing to a line connecting the mastoid processes, into two widely separated 

 very slightly elevated ridges continued forwards to the posterior margins of 

 the post-orbital processes. In Pt. medius, the frontal is deeply furrowed 

 between the roots of the post-orbital processes, in M. spelceus it is elevated. 

 In Pt. medius, the post-orbital processes are very long and curved downwards, 

 separated by a very short interval (in a skull before me 015 inch) from a 

 corresponding process sent upwards from the zygoma, thus almost com- 

 pletely circumscribing with bone the margin of the orbit. In M. spelceus, 

 the post-orbital processes of the frontals are short, and almost horizontal ; 

 the zygoma is slender, and there is no trace of an ascending process. 



The bases of the skulls of Pt. medius and M. spelceus are very similiar, 

 the only difference noticeable being, that, in the former the foramen rotun- 

 dum and foramen ovale are represented by a single opening, in the latter they 

 are distinct. 



In Pt. medius, the caudal vertebrsB are wanting, in 3£. spelceus they are 

 five in number, very short and rather thick. 



The remainder of the skeleton of M. spelceus corresponds closely in form, 

 and in the relative proportion of its parts, with that of Pt. medius. 



I have read with some surprise Prof. Flower's statement* that, in the 

 genus Pteropus, " there is no corresponding ascending process from the zygo- 

 matic arch," — for, in a skull of Pteropus medius, Tern., (compared, above, 

 with that of Macroglossus spelceus') the post-orbital process sent upwards 

 from the zygomatic arch measures 015 inch along its anterior margin, - 15 

 inch across its base, with a vertical height, posteriorly, of more than 010 

 inch. 



The same author, at 1, c. p. 153, remarks that Insectivorous Bats have 

 no post-orbital processes of the frontals. This statement is only partially 

 correct, for although many, perhaps most, genera of insectivorous bats do not 

 possess post-orbital processes, yet in some genera they are not only present, 



* Introduction to the Osteology of the Mammalia, by W. H. Flower, F. R. S. 

 1870, page 152. 



