F. Pitt 105 



ferret skulls averaged 14 ram., against 21 mm. in three polecats. In the 

 M. eversmanni skull that I examined the ridges were as long as those of 

 the European polecat and noticeably different from those in M. faro. 

 This seems to indicate a character in the ferret that is not possessed by 

 either of the other species. In such intangible peculiarities as tempera- 

 ment and disposition the ferret is very different from M. putorins, as is 

 shown by the ease with which it is tamed even after being neglected 

 while young. An adult-caught polecat is quite untameable, and even 

 half-bred ones require constant handling from their earliest youth to 

 make them docile. It takes a very serious fright to make a placid easy- 

 going ferret emit the vile defensive odour, but the hybrids never hesitate 

 to make use of it. In disease-resistance too the ferret differs from the 

 polecat, being less susceptible than the wild animal to some of the 

 diseases met with in captivity. For instance the majority of polecats 

 exhibited at the Zoological Gardens, Regent's Park, succumb more or less 

 speedily to pneumonia, and I have found the hybrids nearly as delicate. 

 In the case of epidemic diseases, such as one of the complaints that get 

 classed under the heading of "distemper," polecat-bred ferrets have in my 

 experience been always the first to take it, and with more fatal results 

 than those of pure ferret descent. For instance I recently lost six ferrets 

 in the following order: first No. 19, a dark female the offspring of a 

 hybrid and an albino ; secondly another dark female. No. 29, whose sire 

 carried polecat blood ; then a fawn ferret, No. 28, full sister to the pre- 

 ceding ; and lastly three white ones. The latter were not only the last 

 to take the disease, but did not succumb nearly so quickly. 



From the foregoing it will be seen that there are quite a number of 

 points of difference between the polecat and ferret, both structural, pig- 

 mental, physiological, and temperamental, so that the grounds for doubt 

 as to whether the one is derived from the other are quite substantial, 

 and the materials are such as to afford a most interesting subject for 

 genetical investigation. 



III. Variation in the Polecat and in the Ferret. 



(a) Variation in the Polecat. It is noteworthy when considering the 

 relationship of the polecat and ferret, that, as far as I can ascertain, no 

 albino polecat has been recorded. Nevertheless it is probable such sports 

 do occur, for unless the specimen passed into the hands of an expert and 

 was examined as to structural details, it would almost certainly be 

 dubbed a feral ferret. The probability is enhanced when we find that 



