Cope.] 5£>b LJan 18> 



tuberous projection of the angle from the anterior edge of the glenoid sur- 

 face. There is a deep fossa at the internal base of thepostglenoid process, 

 which possibly enters a foramen. No postglenoid foramen. 



Although the skull of the Gyclopidius emydinus is more robust than 

 that of G. simus ; the length of the tooth-line is the same. The in- 

 cisive edge of the premaxillary bone displays one empty alveolus, from 

 which the single incisor was easily shed. The canine is not large, and 

 the base of the crown has a regularly convex anteroexternal face ; apex 

 lost. The diastema posterior to it is equal to its diameter. The crowns of 

 the premolars are worn ; they are of about the size and proportions of 

 the G. simus. The true molars differ, as I have already pointed out, in 

 their greater transverse diameter, and the greater anterior prolongation 

 of the anterior horns of the posterior external crescents. The deep notch 

 which is enclosed between this fold and the wall of the crescent in front 

 of it is filled with cementum. As to the form of the true molars, the 

 transverse diameter of the first considerably exceeds its anteroposterior 

 diameter ; in the G. simus the former diameter is equal to the latter. In 

 G. emydinus the last true molar is as wide as its length without the heel - T 

 in the G. simus, the transverse diameter is much less. In G. simus the heel 

 is more prominent, and is recurved into a vertical ridge, which is wanting 

 in the G. emydinus. In G. emydinus this tooth shows but little of the pris- 

 matic character, as the roots are of usual length. 



The lower jaw of this species is not yet known. 



Measurements. 



M. 



Length of skull along base 129 



Length from condyles to posterior edge of zygomatic 



foramen 042 



Length from condyles to palatonareal foramen 063 



*' " " " line of last true molar 071 



" " occipital crests to line of orbits 074 



-'' " " " " facial vacuities 084 



" " " " " ascending process of 



maxillary bones 115 



Length from occipital crest to free end of nasal bones. .12(5 



Elevation occiput, including condyles 045 



" of front at middle of orbit, without molars. . .085 



" " maxillary bone at P-m. iii 015 



" " P-m. i 025 



Width of skull at occipital condyles .0675 



"•; " " " superior edge of meatus auditorius.. . .057 



" " " " middle of zygomatic foramina 092 



" " brain-case at middle of zygomatic foramina. . .029 



" skull at orbits 083 



" " ,, between orbits 047 



" " muzzle at superior edge of nares .0215 



