180 Dr. J. Murie on the Hor?is, Viscera, 



scription. The second clearly establishes intervention of fibro- 

 cartilaginous matrix between the skull and the partially porous 

 osseous substance of the horn. The first brings out the rough 

 irregularly channelled exterior. 



The existence of a third or median horn in the giraffe has 

 likewise been a subject of controversy among anatomists. By 

 some this peculiar middle frontal elevation has been regarded 

 as but an osseous eminence, and not representative of an ab- 

 normally 2)laced additional horn. Other authorities have not 

 hesitated to class it as analogous to the rearmost pair, though 

 developed over the sagittal suture, and short and squat. My 

 colleague Dr. Cobbold * has been at some pains to collate the 

 statements of several excellent zoologists and anatomists, 

 which sustain his independent observation — viz. that the 

 anterior median prominence of the girafie's skull, situate at 

 the junction of the nasals and prefrontals and over the sagittal 

 suture, is a separate indejiendent structure, analogous there- 

 fore to the so-called hinder horns. 



Tlie proofs of its separate ossification and, therefore, epi- 

 physial nature, which I advance in support of those who 

 maintain such a view, rest chiefly on two specimens — one a 

 section of the skull of the young animal already referred to 

 {vide infra) J the other a completely ossified cap removed from 

 the cranium of an adult. In the calf stage, complete absence 

 of bone or germ of ossific centre is indubitable, a thickening 

 of the periosteum alone denoting the future position of the 

 subsidiary piece in question. My sketch from the fresh speci- 

 men (fig. 3), whilst substantiating Dr. Cobbold's observation 

 on the immature giraffe, more clearly displays the sti'uctural 

 condition of the parts than in his diagram [1. c. p. 15). 



Fig. 3. 



Lono-itudinal vertical section of tlie mid frouto-cranial bone and superin- 

 cumbent fibro-periosteal covering of the young c? giraffe, nat. size. It 

 illustrates the rudiment or basal matrix of the as yet undeveloped third 

 horn : fc, fibroid or semicartilaginous periosteal thickening upon ■which 

 the future so-called horn is established ; sk, portion of the skull just in 

 front of the brain. 



* The Intellectual Observer, Aug. 1862, p. 12, with a plate and wood- 

 cut. 



