Vol. 55-] 



OP THE ROCK-FISSTJEE AT IGHTHAM. 



423 



Measurements of Spermophilus- 

 Skulls (in millimetres). 



a 



2 II 



CO "2^ 



Hi 

 ^"1 



1^ 



Front of premaxilla to hinder edge oi 

 parieta^s 



50-0 



21-0 



31-5 



160 

 380 

 25-0 

 100 

 1.50 



9-5 

 140 



8-0 

 15-0 

 120 



4-0 



450 

 20-0 



28-0 



14-5 

 34-0 

 22-0 



9-0 

 14-5 



9-0 

 130 



60 

 14-0 

 11-0 

 ?3-6 



490 



210 



29-0 



15-5 

 320 



21-4 

 11-2 

 140 



9-5 

 120 



7-5 

 150 

 120 



4-5 



540 



38-0 

 100 



130 



Front of premaxilla to hinder edge of 

 nasals 



Front of premaxilla to hinder edge of 



Front of premaxilla to anterior cheek- 

 tooth 



Greatest width across j ugal arch 



„ ,, „ brain-case 



Least interorbital width of frontals 



Orbital diameter, postfrontal to lachrymal . 

 Length of premaxilla in mid-line of palate. 



„ maxilla „ „ 



„ palatine 

 Width of palate outside alveoli 



Length of alveoli of five cheek-teeth 







Measurements of Lower Jaws 

 (in millimetres). 



Back of articular condyle to hinder border 



of incisor 



Back of articular condyle to front border 



of incisor 



Posterior angle to front border of incisor... 



Length occupied by four cheek-teeth 



Hinder border of incisor to back of last 



molar 



Length of diastema 



Length from front of masseter-disc to 



indenture between angle and condyle . . . 





CO 









i 



34-0 



I'll 



-•2 



H 



|5 





31-0 



32-0 



35-0 





35-5 



32-5 



33-0 





34-5 



35-5 



32-5 



33-0 





34-5 



11-0 



9-6 



10-2 



12-0 



13-01 



190 



170 



18-5 







8-0 



7-5 



8*5 





7-5 



18-5 



170 



170 





18-0 



1 In Falconer's figure these teeth measure 11-5 millimetres. 



The skull wants the right jugal arch, the left premaxilla, the 

 occiput and all the teeth ; but there is still sufficient left to 

 trace the outline of the skull, and especially the form of the 

 broad jugal arch. The entire skull is broad and depressed ; 

 the orbits are large ; the cranium is broad, especially in its hinder 

 part, and the surface of the bone is strongly pitted. There 

 is a short, slight median crest at the hinder part of the parietals ; 



