776 



NOTES ON THE VJMPTRE BAT— ALLEN. 



After this ratlier striking' contrast, it is of interest to note the follow- 

 ing" points whicli the two genera possess in eoniinon. showing a close 

 alliance between them. 



Interval between the maxillary canines occupied by the enormous 

 central incisors. Length of central incisors equal to height of anterior 

 nasal aperture. Pterygoid process produced posteriorly in a sharp 



Fi- 5. 



I.llWKK .lAW OF DII'HYLLA AND DESMODVS. 



AsceilililiR ramus nl lower j:iw ,,!' [ a j Diphi/lla cruudata anil { ')) Deamoilns rufiis ; vit-wi-d I'rnm side. Fimr tlinea natural size. 



spine. Tympanic bones inflated, large, nearly of same size, firmly 

 anchylosed to the temporal bone; the oi)ening for membrane small. 

 Mesopterygoid fossa narrowed anteriorly and progressively widened 

 posteriorly. Ascending ramus of the lower jaw high, with shallow sig- 

 moid notch and rudimental angular i^rocess. The lower jaw back of 



Fig. 6. 



WINi; MEJIBRAXE OF DIPHYLLA ECAUDATA. 



Anteniir view. One-half natural size. 



mentuni provided with deep i)it in which during articulation the max- 

 illary central incisors are received. All teeth sectorial; lower incisors 

 and canines pass well in front of upper incisors in closure of jaws. 



DipJiylia is more generalized than Dcsmodns. The face axis is longer, 

 the nasal chambers more ample, the maxillary incisors and canines 

 weaker, while the teeth are less reduced in numbei-. 



Diphylht is, on the whole, a less specially adapted form than Jh.siitodus. 

 The proportion of first rietacarpal bone and phalanges are as is the 



