304 SEXUAL selection: mammals. PartIL 



number, though very variable in distinctness. From 

 this condition there is but a very small step to the 

 complete absence of spots at all seasons in the adults ; 

 and lastly, to their absence at all ages, as occurs with 

 certain species. From the existence of this j)erfect 

 series, and more especially from the fawns of so many 

 species being spotted, we may conclude that the now 

 living members of the deer family are the descendants 

 of some ancient species which, like the Axis deer, was 

 spotted at all ages and seasons. A still more ancient 

 progenitor probably resembled to a certain extent the 

 Hyomoschus aquaticus — for this animal is spotted, and 

 the hornless males have large exserted canine teeth, 

 of which some few true deer still retain rudiments. It 

 offers, also, one of those interesting cases of a form 

 linking together two groups, as it is intermediate in 

 certain osteological characters between the pachyderms 

 and ruminants, which w^ere formerly thought to be 

 quite distinct.*^ 



A curious difficulty here arises. If we admit that 

 coloured spots and stripes have been acquired as orna- 

 ments, how comes it that so many existing deer, the 

 descendants of an aboriginally spotted animal, and 

 all the species of pigs and tapirs, the descendants of 

 an aboriginally striped animal, have lost in their adult 

 state their former ornaments ? I cannot satisfactorily 

 answer this question. We may feel nearly sure that 

 the spots and stripes disappeared in the progenitors of 

 our existing species at or near maturity, so that they were 

 retained by the young and, owdng to the law of inheritance 

 at corresponding ages, by the young of all succeeding 

 generations. It may have been a great advantage to 



*^ Falconer and Cautley, ' Proc. Geolog. Soc' 1843 ; and Falconer's 

 ' Pal. Memoirs,' vol. i. p. VjG. 



