C. J. Bond 125 



singleness and doubleness of dose, and besides reciprocal gametic 

 introduction, and besides intermediary action of restraining factors, 

 and besides colour basis and colour developer factors, there still remains 

 some crametic cause for the abnormal behaviour of the unit characters in 

 the individuals with irregular eye colour pattern. Now it seems possible 

 that this unexplained irregularity of pattern may depend on some 

 deficiency in integration of the dominant duplex factor, some ab- 

 normality in the way in which it is present in the gamete which carries 

 it, or in the way it is incorporated by the gamete which carries the 

 recessive or the alternative character. 



Of the characters possessed by gametic factors two of the most 

 important are total VOLUME, that is, size or quantitative presence, and 

 DEGREE OF INTEGRATION, that is, qualitative presence. 



The reduction of the total volume of gametic factors occurs probably 

 during gameto-genesis and the important point is that this reduction of 

 volume may apparently take place with or without a concomitant 

 process of partial disintegration of the factor concerned into its 

 subordinate units. That is to say reduction of volume may be quanti- 

 tative or qualitative. 



Thus the factor for self-eye colour has, in ordinary individuals, 

 a definite total volume ; it possesses a definite capacity to spread 

 epistatically over the whole anterior surface of the iris and so to produce 

 the self-coloured pattern in the duplex eye. 



In certain less numerous cases (14 out of 88) the volume of this 

 factor is reduced and its epistatic influence is restricted to a circular 

 zone of iris round the pupil, and the ring pattern appears ; in other 

 individuals it is limited to certain patches on the iris and produces the 

 SPOTTED PATTERN ; in Others again (3 cases in 200) it only operates over 

 certain sectors of the iris and then forms the RAY pattern. 



In all these cases the reduction in volume occurs in association with 

 a qualitative and disintegrative change, a change in which the original 

 factor for self-colour undergoes subdivision into subordinate factors 

 independently controlling different areas (either rings, or patches, or 

 rays) of the same iris. 



In other cases again there is no subdivision or disintegration and the 

 reduction in volume (or capacity of influence) of the factor for self- 

 colour takes the form of quantitative dilution, of deficient pigment 

 saturation over the whole of the anterior surface of the iris, and in this 

 way the various tints of the duplex pattern, from yellow to dark brown, 

 are brought about. 



