The Philippine Journal of Science, 



D. General Biology, Ethnology and Anthropology. 



Vol. VI, No. 4, August, 1911. 



THE SKELETON IN THE FLYING LEMURS, GALEOPTERID/E. 



By R. W. Shl-fei,dt. 

 {Washington. D. C.) 



( Conoluded. ) 

 THE SHOULDER GIRDLE. 



Comparative anatomists have observed great differences in tlie mor- 

 phology of the shoiilder girdle among the various representatives of the 

 Insectivora, not finding this structure alike in any two families of the 

 order. CynocephaJus has the two bones composing it, the clavicle and 

 the scapula, remarkably well developed and in full proportions for the 

 size of the animal. 



Making the usual articulations with the sternum and the scapula, we 

 find the clavicle to be a large, strong bone. Its extremities are enlarged 

 to support the articulatory facets. The shaft is stout with its continuity 

 of nearly uniform caliber, and presents two curvatures. About two- 

 tliirds of its mesial length offers the least apparent cui-vature, being 

 slightly and uniformly bent so as to present the concavity to the front; 

 the remaining third of the bone makes a very decided curve to arrive 

 at its scapular articulation. This part of its shaft is somewhat antero- 

 posteriorly flattened, or rather compressed, being nearly flat behind and 

 concave in both directions anteriorly. In the normally articulated skele- 

 ton, this curvature allows the clavicle to pass over the prominent coracoid 

 process of the scapula, and brings its outer extremity in articulation 

 with the external process of the two apophyses which finish off the upper 

 end of the acromion process of the scapula. In one of the specimens 

 from the Bureau of Science (2) the clavicle has a length of 3.6 centi- 

 meters while it is only 3.4 centimeters in the Steere specimen, and 3.5 

 centimeters in the remaining individual (3). Therefore it averages 3.5 

 centimeters in length, and is about as long as one of the thirteenth pair 

 of true, or vertebral, ribs of the skeleton to which it belongs. 



It is somewhat remarkable that the scapula in some specimens of 

 Oynocephalus does not fully ossify; this lack of ossification occurs in the 

 so-called "blade" of the bone, (Plate II, figure 5 (1) : see explanation 



185 



