H. H. NEWMAN. 



The observed class (b), 41 sets, is several sets in excess of ex- 

 pectation, but not enough to seriously effect the theory of breed- 

 ing proposed. The observed class (c), 43 sets, is several sets 

 too low, but it is very probable that the five discarded male sets 

 referred to above belong to this category. On the whole, then, 

 the observed and theoretical proportions of the categories of 

 offspring are as close as could be expected in 140 matings, and 

 this fact supports the general statement as to the modes of 

 inheritance of these anomalies stated above. 



2. The Genetic Relation Between Scute and Band Anomalies. 



There is a very intimate genetic relationship between band 

 and scute anomalies, as was brought out in the previous paper 

 (Newman, '15). Sometimes a band anomaly is inherited as such 

 in some offspring of a set, and as a scute anomaly in others; and 

 the localization in all cases is so exact that there can be no doubt 

 about the genetic equivalence of the two anomaly phases. 



In Figs. 1-8 is arranged a series of drawings of scute anomalies 

 leading up to band anomalies. The transition is more readily 

 made out from the conditions in the bony plates underlying 

 the scutes. Fig. la represents the appearance from the exterior 

 where only the scute is visible; Fig. ib shows the underlying plate 

 condition. Similarly with Figs. 2a and 2b, etc. In Fig. 6, a 

 and b, we see that the more fundamental anomaly is a transverse 

 splitting of the bony plate involving only one unit. Fig. 7, 

 a and b, constitutes an incipient or minimal double band, while 

 Fig. 8, a and b, represents a band doubling of moderate extent 

 involving six scutes. Such band doublings may involve more than 

 half of a band or there may be extensive doubled regions separated 

 by single or undoubted regions. 



Since the bony plates are fully laid down only during post- 

 embryonic life, it is impossible to study these structures in the 

 fetuses that are taken from the uteri of the mothers; but the scute 

 condition, for one who has made a study of the subject, serves as a 

 very definite index of the condition of the bony plate; and the 

 scutes are well defined long before birth. For example, whenever 

 a scute is found with a deep notch above dividing the scute into 

 two nearly equal cusps (as in Fig. 30), one can be sure that the 



