1880.] 4t>0 [Cope. 



Chlamydoplwrus ; a postglenoid only. 

 Manis ; post zygomatic only. 



Megalonyx ; postsquamosal and supratympanic ; a closed fissure at posi- 

 tion of postglenoid. A large foramen below the usual position of mastoid. 

 Bradypus and Cholcepus ; no foramina. 



PiODENTIA. 



In this order, so far as yet observed, the supraglenoid and postparietal 

 foramina are never present, while the mastoid is rarely, and the sub- 

 squamosal is generally, represented. The ridge connecting the zygoma 

 with the inion being weak, the difference between this foramen and the 

 postsquamosal is less marked in this order than in the Marsupialia. It is, 

 however, always on the inferior border of the squamosal bone. 



Lepus and Lagomys ; no foramina. 



Lagidium ; no foramina. 

 Cercolabes ; no foramina. 



Lagostomus, Geomys and Erithizon ; an enormous postglenoid without 

 internal canal. 



Capromys, U&logenys, Sciurus, Haplodontia, Hesperomys, Mus ; post- 

 glenoid and postsquamosal only. 



Hystrix, Hydrochcerus, Neotoma and Arvleola ; postglenoid and post- 

 squamosal foramina confluent ; no others. 



Castor, Cynomys and Spermophilus ; postglenoid, postsquamosal and 

 mastoid. 



Insectivora. 



The foramina are very much as in the Bodentia in the smaller forms, 

 and as in the Carnivora in the larger. 



Blarina, Condylura and Scalops ; postsquamosal only. 



Erinaceus ; postglenoid and postsquamosal only. Mystomys the same, 

 according to Allman's figures. 



Centetes ; postglenoid, postparietal and mastoid. 



Solenodon (from Peters' figures) ; postglenoid and postparietal, 



Chiropteiia. 



In some members of this order the foramina are, as in many Carnivora, 

 limited to the postglenoid and postparietal. 



Scotophilus (fuscus); postglenoid, postparietal and mastoid. 

 Pteropus ; postglenoid, subsquamosal and postsquamosal. 



Carnivora. 



In this order the foramina are few in number, and are very well defined. 

 None of them possess more than three, while the specialized forms ; both 

 terrestrial and aquatic, do not possess them. 



Tricl.ecus and Aretocephalus ; no foramina. 



Pltora • ; a rudimental postglenoid. 



