572 



it probably reappeared, and from thence continually increased in 

 potency and complication. 



This conception according to my view is strengthened by the fact, 

 that also among the Suidae a tendency to the formation of bony 

 protuberances on the dorsal side of the skull undoubtedly occurs and 

 appears in stronger manifestation in the male sex than in the female, 

 as is shown by the monstrous skull of the male African wart-hog. 



6. In Protoceralinae likewise the skull of the male only was 

 provided at its upper side with a complete set of paired bony 

 excrescences. 



7. According to Marsh both sexes of the Dinoceratidae possessed 

 these bony protuberances (and the large dagger-like tusks besides), 

 yet in the male they grew unto a larger size than in the females. 

 We might conclude from this tiuil the tendency to the production 

 of bony knobs on the skidl is even oldei' than the separation of 

 Ungulates into Artio- and Perissodactyles. 



8. The annual shedding of the antlers and their regeneration 

 in Cervinae is apparently connected with the rut. The same appears 

 to be the case in Antilocapra. 



9. The abovenientioned bony processes on the head of Gii-affidae, 

 (sensu latiori) Suidae, Protoceralinae and Dinoceratidae, cannot rea- 

 sonably be considered as really practical weapons, as they are far 

 too cumbrous and hypertrophic for that. Neither can this be the 

 case with the antlei'S of most Deer oi- the horns of numerous Antilopes, 

 Cattle, Sheep, and Goats. 



On the other hand they wear to a \ ery high degree the character 

 of sexual attributes, in their exuberance, unpractical build, curious 

 complication, obviousness and variability. 



10. In the first (primitive) members of the Ruminantia antlers 

 and horns a[)parently arose at a relatively late stage, though this 

 may be furthei' removed in the geological past than is generally 

 supposed. In any case the appearance or return of this feature is 

 younger than the remaining peculiarities of Ai-tiodactyla. 



As I consulted the literature on the subject, I found that in 

 considering horns and antlers as sexual attributes, I had come to a 

 similar conclusion as the well-known popular author on questions 

 of evolution in Zoology, Bölsche, has set forth in his Tierbuch 

 IV, der Hiisch. • Yet on the first cause of the origin of frontal 

 appendages our opinions disagree, for Bölsche sees in the 

 excrescences on the roof of the skull of so many Ruminants nothing 

 more than originally purely ornamental attributes, and ascribes their 

 birth to a periodical exuberance of energy of growth, manifesting 



