450 BR. R. BROOM ON TUIC 



auchylosed that it is impossible to do much more than speculate 

 on the structure. Dobsou figures a uearl}' adult skull of one 

 species which reveals some sutures, but only a very young skull 

 could clear up most of the points in doubt, and until recently, 

 so far as I am aware, no very yoiuig specimens have ever been 

 obtained by any scientist. While residing at Stelleubosch, though 

 I collected many adult Chrysochloris^ I only succeeded in getting 

 about half a dozen young specimens, and unfortunately I have 

 no specimens which would show the early condition of the 

 chondrocranium. Still, the skull of the newly-born Chrysochloris 

 hottentota, which I have examined, is in such an interesting stage 

 of development that it reveals clearly the nature of practically all 

 the cartilaginous as well as the osseous elements. 



Prof. J. P. Hill has very kindly had the head of the young 

 Chri/sochloris hottentota sectioned for me by his laboratory 

 assistant, Mr. F. Pittock, and the facts revealed in the sections 

 have been confirmed and amplified by the study of a prepared- 

 skull of a slightly older L'hri/socTdoris asiatica. 



Skull of young Chrysochloris asiatica. 



The skull measures in greatest length 13"5 mm., and the basal 

 length from the basioccipital to the premaxilla is 10"7 mm. The 

 maximum width is 9'5 mm., and height 7*5 mm. 



When viewed from above, the large size of the brain region, 

 the narrowed orbital, and the short narrowed facial region give 

 the skull a slight superficial resemblance to that of a small bird. 



The premaxillie are small, irregularly square-shaped bones 

 which articulate by one side with the maxilla? and by another 

 -with the nasals. They contain the already calcified points of the 

 three milk-incisors. The premaxilla forms a distinct portion of 

 the hard palate behind the incisors and in front of the anterior 

 palatine foramina. 



The maxilla forms the greater part of the hard palate. Already 

 the milk-canine, the three milk-molars, and the first molar are 

 partly calcified. The maxilla forms about twice as large a part 

 of the side of the snout as does the premaxilla. Thexe is a large 

 foramen for the large maxillary branch of the Vth nerve. The 

 most remarkable thing about the maxilla is the wa}^ in which it 

 forms the jugal arch. There is no trace of a jugal bone, and the 

 whole arch is formed by a backward process of the maxilla which 

 runs back as far as the glenoid cavity and articulates with the 

 squamosal. 



The nasals are relatively short. They measure 4'5 mm. in 

 length, and the greatest measurement across the two is at the 

 uppar end, where it is 3 mm. In front the transverse measure- 

 ment is 2 mm. 



The lacrimal is very small and cannot be satisfactorily made 

 out in this skull, though it can be detected in the sections of the 

 earlier stase. 



