i88 Darwin, and after Darwin. 



"Elsewhere (Origin of Species , p. 158) Mr. Darwin points out 

 that modifications which appear to present obvious utility are 

 often found on further examination to be really useless. This 

 latter consideration, therefore, may be said to act as a foil to 

 the one against which I am arguing, namely, that modifications 

 which appear to be useless may nevertheless be useful. But 

 here is a stiil more suggestive consideration, also derived from 

 Mr. Darwin's writings. Among our domesticated productions 

 changes of structureor even structures wholly new not unfre- 

 quently arise, which are in every way analogous to the apparently 

 useless distinctions between wild species. Take, for example, 

 the following most instructive case : 



Fig. 2. Old Irish Pig, showing jaw-appendages (after Richardson). 



"' Another curious anomaly is offered by the appendages 

 described by M. Eudes-Deslongchamps as often characterizing 

 the Normandy pigs. These appendages are always attached 

 to the same spot, to the corners of the jaws ; they are cylindrical, 

 about three inches in length, covered with bristles, and with 

 a pencil of bristles rising out of a sinus on one side ; they have 

 a cartilaginous centre with two small longitudinal muscles ; 

 they occur either symmetrically on both sides of the face, 

 or on one side alone. Richardson figures them on the gaunt 

 old Irish Greyhound pig; and Nathusius states that they 



