1904.] 



SKULL OP THE GIRAFFE. 



151 



in a footnote, dated April 30th, on p. 295 of the above-mentioned 

 memoir), and suggested that either the base of the primaiy horn 

 or ossicusp must have been hollowed out by the absoi-ption of its 

 svibstance as the sinus extended upwai'ds, or that the primary 

 ossicusp must have been lifted up bodily upon a hollow dome or 

 cone of the f ronto-parietal bone, while a corresponding downgrowth 

 of bone occurred fi'om the margin of the ossicusp so as to cover up 

 the lower parts of this conical eminence. On the former assumption 

 the layer of bone which in text-fig. 9 (p, 155) forms the boundary of 

 the uppei-most pai't of the fronto-pariet;il vacuity would belong to 

 the ossicusp, and on the latter to the fronto-parietal bone. So 

 much of the sutui'e as can be recognised in the section certainly 

 rises so as to run parallel to the margin of the sinus, and the 

 lamination and the density of the bone that forms the immediate 

 lioundary of the vacuity also favour the second view. 



Desiring to know more about the relations of the great fronto- 

 parietal sinuses, Pi'of . Lankester had the skull cut across into six 



Skull of Giraffe, left side ; key-figure, a little larger than one-sixth (linear) of the 

 natural size, showing the directions in which the skull was cut. 



pieces along planes which he indicated, and the inclinations of 

 which are shown in text-fig. 4 by the lines 1 — 5. The appearances 

 presented by these sections being new to science, and the sections 

 promising to prove of greater interest in proportion as more 

 knowledge is obtained of the skidl of the Okapi, Prof. Lankester 

 had drawings made, which he handed over to me with a request 

 that I should write a short description of them foi- publication. 

 My thanks are hereby tendered to Prof, Lankester for the use of 

 the drawings. 



