Fig. 14. Cores to Loops, which may consist either of single lines, here called _rods_, or of a recurved line or _staple_, while the ridges that immediately envelops them is called an _envelope_ 76 Fig. 15. Cores to Whorls 77 IX.--Fig. 15. Transitional patterns, enlarged three times, between Arches and either Loops or Whorls 79 X.--Fig. 16. Transitional patterns, as above, but between Loops and Whorls 79 XI.--Fig. 17. Diagram showing the nine genera formed by the corresponding combinations of the two letters by which they are expressed, each being _i_, _j_, or _o_ as the case may be. The first two diagrams are Arches, and not strictly patterns at all, but may with some justice be symbolised by _jj_ 80 Fig. 18. Ambiguities in minutiae, showing that certain details in them are not to be trusted, while others are 92 XII.--Fig. 19. The illustrations to Purkenje's _Commentatio_. They are photo-lithographed from the original, which is not clearly printed 86 XIII.--Fig. 20. Enlarged impressions of the same two fingers of V. H. Hd., first when a child of 2-1/2, and subsequently when a boy of 15 years of age. The lower pair are interesting from containing the unique case of failure of exact coincidence yet observed. It is marked A. The numerals indicate the correspondences 92 XIV.--Fig. 21. Contains portions on an enlarged scale of eight couplets of finger prints, the first print in each couplet having been taken many years before the second, as shown by the attached dates. The points of correspondence in each couplet are indicated by similar numerals 93 XV.--Fig. 22. The fore-finger of Sir W. J. Herschel as printed on two occasions, many years apart (enlarged scale). The numerals are here inserted on a plan that has the merit of clearness, but some of the lineations are thereby sacrificed 95 Fig. 23. Shows the periods of life over which the evidence of identity extends in Figs 20-22. [By an oversight, not perceived until too late for remedy, the bottom line begins at aet. 62 instead of 67] 97 CHAPTER I INTRODUCTION