sect, x.] INTRODUCTION. 57 



semi-feral herd in Queensland was described by Tegetmeier, Field, 

 xlviii. 1876, p. 281. The skin was black and like india-rubber. Careful 

 examination shewed no trace of hair, or any opening of a hair-follicle. 

 In Turkestan, in the year 1886, I heard of one thus travelling, but failed 

 to see it. ' Hairless' dogs in S. America remain distinct (Belt, I, c). 



Of discontinuous Substantive Variation in bodily proportions a 

 single example must suffice. Among domestic animals of many 

 kinds, races are known in which the bones of the face do not grow 

 to their full size, while the bones of the jaw are, or may be, of 

 normal proportions. Familiar examples of this are the bull-dog, 

 the pug, the Japanese pug, the Niata cattle of La Plata 1 , some 

 short-faced breeds of pigs, and others. In the case of these 

 domestic animals the part which Selection has taken in their pro- 

 duction is unknown, and the magnitude of the original variations 

 cannot be ascertained. It is nevertheless of interest to notice 

 that parallel variations have occurred in distinct forms, and I 

 think that this is to some extent evidence that the variations 

 were from the first definite and striking. As regards the dogs 

 even, there is a presumption that the short face of at least the 

 Japanese pug arose independently from that of the common, or 

 Dutch pug (as it used to be called), but as to this the evidence is 

 insufficient. Among the dogs' skulls found in ancient Inca inter- 

 ments, a skull was found having the form of the bull-dog. 

 Nehring, Kosmos, 1884, XV. As these remains belong to a 

 period before the European invasion, it is most probable that 

 this bull-dog breed arose independently of ours. 



Apart however from domestic animals there is evidence as to 

 the origin of short-faced breeds. This evidence, which is not so 

 well-known as it deserves to be, is provided by the occurrence of a 

 similar variation in fishes. Darwin in speaking of the evidence as 

 to Niata cattle makes allusion to the case of fishes in a note 2 , 

 quoting Wyman as to the cod, which occurs in a form known to 

 fishermen as the "bull-dog" cod. The interest of this obser- 

 vation is increased by the fact that it does not stand alone, but 

 similar variations have been seen in the carp, chub, minnow, pike, 

 mullet, salmon and trout. In the last-named there is even 

 evidence of the establishment of a local race having this singular 

 character. 



Carp (Cyprinus carpio). " Bull-dog "-headed Carp have often been 

 described. The face ends more or less abruptly in front of the eyes, 

 while the lower jaw has almost its normal length. The front part of 

 the head is bulging and prominent, giving the fish an appearance which 

 several authors compare to that of a monumental dolphin. A good 

 figure of such a specimen is given by G. St Hilaire, Hist, des Anom., 

 ed. 1837, I. p. 96, where a full account of the older literature of the 



1 C. Darwin, Animals and Plants tinder Domestication, 2nd edition, i. p. 92. 

 - Ibid., p. 93, note. 



