30 SJOSTEDTS KILIMANDJARO-MERU EXPEDITION. 2. 



symmetrically in the mesial line but more or less completely on the right side of the 

 same (fig. 2). Above the right orbit there is quite a big boss with a basal diameter of 

 about 4 4V a cm. and a height above the orbit of nearly 4 cm. In front of the right 

 parietal horn is another boss with a diameter of about 4Va cm., and a third on the right 

 side of the occiput (figs. 1 & 2). The last is more irregular than the others almost 7 cm. broad 

 and 4 cm. long. On the left side there is no extra protuberance on the thickened roof 

 of the orbit. In front of the left parietal horn only a small wartlifce tuberosity is seen, 

 the diameter of which is about 1 cm. The occiput of the left side has no osseous excres- 

 censes. The striking assymmetry in the armament of the skull extends, however, still 

 further as the two main parietal horns are remarkably different in size and shape (fig. 2), 

 the right horn being somewhat shorter but much thicker and stouter than the left, which 

 is proved by the following measurements. The length of the front surface of the right 

 horn may be estimated to 15 cm. and that of the left to 17 cm. The former is more cy- 

 lindrical and growing from a bigger base than the latter. It retains at the top surface 

 a diameter of nearly 6 cm (58 mm. ) while the diameter of the left horn is at the top end 

 42 45 mm. The top surfaces are quite different, too, that of the left being evenly 

 rounded and that of the right almost flat. With other words the right horn has such 

 a shape as if a body shaped like the left horn and consisting of a plastic mateiial had 

 been hammered or beaten down from the top end, making it flatter above and thicker. 

 Such a force has also, no doubt, exercised its influence on the right horn as will be ex- 

 plained later on. 



As regards the assymmetrical arrangement of the armament this old bull of Giruffu 

 tippelskirchi resembles the bull of the Giraffe from South Lado which LYDEKKER (Proc. 

 Zool. Soc. 1904 p. 207) has termed Giraffa catnelopardalis cottoni. In the latter there 

 is also an azygous orbital horn on the right side (although placed somewhat lower) and 

 the right main horn is decidedly larger than the left horn. In addition to this LY- 

 DEKKER' s figure (1. c. textfig. 25 p. 208) shows an azygous osseous boss in front of the 

 right parietal horn of the South Lado Giraffe just as in the present specimen, although 

 nothing is mentioned about this in the text. The author quoted has also stated that, 

 according to Major POWELL-COTTON, all the male Giraffes from the locality in question 

 seem to be furnished with a similar right orbital horn. The question arises now, how 

 may this assymmetry in the armament of the adult bulls of the Kilimandjaro and South 

 Lado Giraffes be explained? It appears to me that an explanation is very near at hand, 

 viz. that the Giraffes of these two races have aquired the habit of constantly using the 

 right side of the head when butting. They have thus become right-headed if such 

 an expression may be allowed as an analogy to right-handed and left-handed . When 

 the animals thus are constantly knocking just the right side of the head against their 

 antagonists, or other objects, the irritating force produced by this action influences the 

 bony tissue especially the periost of this side of the skull above all in such places which 

 are most exposed to the blows as, for instance, the upper brim of the orbit, the right side 

 of the frontal and nasal surfaces etc. and in such places the living tissue responds to the 

 exterior force by producing exostoses. It is a wellknown fact that a lesion of the sur- 

 face of a bone, that is its periost, is apt to produce splint or exostoses. When the Gi- 



