238 



HARRIS HAWTHORNE WILDER. 



so that I wish to make an appeal for others to undertake to in- 

 vestigate the same subject. In the study of friction-skin may 

 be found taxonomy, morphology, ethnology, genetics, as well as 

 the practical application to problems of individual identification. 

 It must be confessed that there is at first a large amount of detail 

 which must be acquired, as well as a certain amount of nomen- 

 clature. The bibliography, however, if that which deals with the 

 special work on apical patterns ("finger-prints") be disregarded, 

 is not large, and as it is for the most part recent it can be readily 



. A/a. 



FIG. 37. Tracings of the only calcar patterns in my entire collection, outside 

 of the two families considered below. 



obtained. Unlike most biological material, that concerned here 

 is readily obtained, and easily kept, a series of prints being 

 for most purposes more convenient for study than the actual 

 objects; the prints, too, are more accurate records of the facts 

 than are any drawings or even photographs. 



We who have been at work along this line are in great need of 

 collaborators. We are firmly impressed with the belief of the 



