IlAITtLESS DUIKEU AND DOG, AND I^ULLD0f4-HEADED CALE. 251 



In addition to the peculiarities of the compressed snout and 

 tlie open palate, the skeleton and viscera exhibited more 

 primitive and generalised characters than those normally 

 belonging- to the ruminating ungulates, such as the simple 

 stomach, the subdivision of the liver into lobes, the smallness 

 of the ctecum, the simple, unlobed condition of the kidney, etc. 



It appears that in this strain of cattle there was a distinct 

 tendency for sudden breaks to occur in the hereditary trans- 

 mission, and since some four similar bulldog-headed calves 

 had originated in the strain, it is obvious that the breaks or 

 accidents which occurred were all of a similar nature. 



Owing to these breaks in hereditary transmission the specific 

 moulding power in the embryo had been weakened ; and the 

 germ had to fall back, so to speak, on distant memories of 

 ancestral history, and consequently the appearance of certain 

 primitive characters might have been anticipated. 



The erratic manner in which the abnormalities appeared must 

 also be noted, since with the same parents perfectly normal 

 offspring were born both before and after the birth of the 

 bulldog-headed calves. It should be noticed that it was 

 quite the same in the case of the hairless duiker and fox- 

 terrier. 



The present evidence shows that in all probability these 

 mutations, sports, or moustrosities arose suddenly through 

 mishaps in the mechanism of hereditary transmission and not 

 throuo-h environmental conditions. 



EXPLANATION OF PLATES X— XIII, 



Illustrating Dr. E. Warren's paper " On a Black, Hairless 

 Duiker and Dog, and a Bulldog-headed Calf." 



PLATE X. 



X _2_. Pliotogi-apli of iiioimtecl black hairless duiker (offspring 

 No. 5) : died when two years of age. 



