164 CHARLES MIDLO AND HAKOLD CUMMINS 



ing degrees of elevation and circumscription of fetal pads 

 during the period of ridge differentiation. The maximum 

 pattern intensity of a single configurational field (value 1.0, 

 applying to whorls and S-patterns) reflects the existence dur- 

 ing that period of a pad having full qualities of elevation and 

 circumscription. At the opposite extreme, an open field (value 

 0) represents a configurational resultant of loss of elevation 

 and circumscription of the pad at the stage of ridge differenti- 

 ation. Between these extremes, the sequence of pattern in- 

 tensity values represents a sequence of gradations of pad 

 conformation. Most closely related to the complete suppres- 

 sion of those qualities of pads which condition patterns, as dis- 

 tinguished from open fields, is that state which brings about 

 but a slight disarrangement of ridges, such as we have char- 

 acterized as a "vestige", which may be occasionally recog- 

 nized as an approach to a specific pattern type and so 

 designated in the original formulations (L vestige, W vestige, 

 S vestige). The term "vestige" has been used because of its 

 wide acceptance and for the want of a term which would be 

 free of its evolutionary implication. We emphasize again 

 that no sense of evolutionary sequence is intended, for if 

 effort were made to identify such configurations as steps in an 

 evolutionary series, it would be first necessary to establish 

 their true nature as vestiges rather than as nascent pattern 

 formations. It is true that real nascency is evidenced in most 

 prosimians and in some platyrrhines ; but demonstrable 

 nascency is associated with lack of complete formation of 

 epidermal ridges. When ridges are imperfectly formed the 

 variations in pad characteristics and their varying produc- 

 tions of configuration types, as discussed above, are more 

 or less dissociated. A pad having all the qualities of full 

 elevation and circumscription may, nevertheless, bear an im- 

 perfectly constructed configuration, the imperfection being 

 due solely to the discontinuities of ridge formation. Under 

 these circumstances a "vestige" justifies consideration as a 

 nascent pattern; were the epidermis advanced sufficiently to 

 possess completely formed ridges the pattern would have 



