THE SKELETON IN THE FLYING LEMURS. 



209 



in any of the skulls from the Philippines. Posteriorly^ we find that the 

 form of the occipital area varies to some extent, though as a rule it is 

 lower and more rounded superiorly in slcuUs of Cynocephalus than in 

 any of the others. In the Malayan skulls it tends to become more lofty 

 and oblong in outline, its width averaging nearly double its height. 



In Cynocephalus the mandible is as a rule, in specimens of the same 

 age and sex, a considerably stronger and deeper bone than in any of the 

 Malayan species. (Compare numbers 121749 and 168.) 



Mr. Gerrit Miller has pointed out to me the fact that the milk teeth 

 in Philippine forms (volans) more or less resemble the permanent 

 teeth in any of the Malayan species. This is well seen in two skulls 

 prepared for the purpose, namely, number 121854 S (Malayan) and 

 number 105 S from Bohol. To compare all the dental characters would 

 require too much space here. They vary in the two genera and in old age 

 ..wear down considerably. 



Trunk skeleton. — Passing to the trunk skeleton it is to be noted that 

 apart from the fact that all flying lemurs possess 7 cervical vertebras, and 

 as a rule 13 dorsals, they may vary very decidedly in the niimber of the 

 lumbar vertebra, as the following table tends to show. 



Vertebrw in Galeopteridw. 



Specimen. 



Number of vertebrae. 



Cervical. 



Dorsal. 



Lumbar. 



McGregor specimen in personal collection 



No. 49640, National Museum, ad. J .__. 



7 

 7 



13 

 •13 

 13 



7 

 6 

 5 





" The lath supports a pair of free ribs. 



Moreover, the characters of some of the vertebrae are different, as for 

 instance, in the atlas. In Gahopterus (number 49640) this bone is 

 nearly square in outline, and possesses a faiiijr well developed neural 

 spine, situated anteriorly. There is no evidence whatever of such a spine 

 in the atlas of Cynoceplialus, in which genus this vertebra is very much 

 wider transversely than it is longitudinally. The transverse processes 

 of the lumber vertebrse in Gahopterus (number 49640) are strongly 

 developed, in every case springing from the entire side of the centrum, 

 and are directed outward and forward. They are much smaller in the 

 Steere specimen {Cynocephalus) , and in the specimens of this genus 

 sent by McGregor from the Philippines they are nearly entirely absent. 

 Some unimportant differences are seen in the sacral and caudal vertebrse 

 of the specimens here under consideration and, everything else being 

 equal, the ilia of the pelvis in Cynocephalus are longer than in the Ma- 

 layan species. 



