SKELETON IN THE FLYING LEMURS. 147 



half of the inferior portion of the occipital condyles constitutes the sole 

 part of the skull that falls below this plane, the roof of the mouth being 

 only slightly above it. This latter ai-ea is laterally bounded by the 

 teeth, but has a free premaxillarj' margin in front. Its outline is a broad 

 U with its convexity forward. All sutures among the bones, maxillaries, 

 premaxillaries, and palatines have been entirely absorbed, without leaving 

 the slightest trace of their original lines of articulation. The surface is 

 extremely smooth, being slightly concave from before, baclovard, and 

 rather more so from side to side. The palatine foramina are minute and 

 are situated far back, one on either side, <!lose to the margin of the 

 posterior nares, and even posterior to the anterior peripheries of the same, 

 indicating that the palatal bones contribute but a small share to the bony 

 roof of the mouth. This latter, anteriorly, is deficient in bone, there 

 being a median, circular vacuity found there between the premaxillaries. 



Jutting into this anterior palatine fossa, in the middle line from 

 behind, is a shai-p, free spine; this is the anterior apex of the vomer. 

 (Plate I, figure 1.) In some skulls (8, 3) this free anterior end of the 

 vomer is in contact, or may unite, with the produced median extremities 

 of the premaxillaries, and thus convert the palatine fossa into a pair of 

 anterior palatine foramina, each elliptical in outline with the major axes 

 directed longitudinally. Owen's skull had this formation, but not so the 

 one collected bj' Steere, wherein the sharp-edged alveolar incisor margin 

 is noncontinuous to the extent of at least 5 millimeters in the median 

 part. Both skulls from- the Bureau of Science agree with Owen's 

 figures (cited above) in that the anterior spine of the vomer is produced 

 forward, bifurcates, and each minute bifurcation either meets, or coos- 

 si fies with, the premaxillary of its own side. This character at once 

 commands attention upon glancing at the basis cranii of the skull. At 

 the hinder boundary of the vault of the buccal cavity we see the posterior 

 narial apertures. Each is rounded in front, with the convexity so directed, 

 the free margins being embellished with a raised osseous rim' that is 

 continued backward, on either side, to terminate as the minute inferior 

 fork of the bifurcation of the hamiilar process of the sphenoid. The 

 posterior nasal spine is rather large with rounded apex. It occurs in 

 the imaginary plane passing through the centers of the second molars. 

 As apertures, the posterior narial ones are considerably compressed in the 

 vertical direction, which is compensated for by their width. 



Each z)^gomatie arch has a broad base anteriorly, being composed, as 

 usual, of the malar and maxillarj^ bones, its base line including rather 

 more than the second premolar and all three molars. Standing well out 

 from the side of the face, this part of each zygomatic arch has its inferior 

 surface directed downward and outward at an angle of about 45° with 

 the median plane (Plate I, figure 1). 



Although the teeth are structures not belonging to the osseous system 



