H. H. NEWMAN. 



I. The Difficulties in the Way of Accurately Analyzing the Data. 



It would be interesting to analyze the data given in the tabu- 

 lation above, but before an intelligent analysis can be made some 

 of the chief sources of error should be pointed out. 



1. Perhaps the most obvious hindrance to accurate analysis of 

 the data appears in the fact that we cannot be certain, if more than 

 one anomaly appears, that the inheritance is solely from the 

 mother, for there must obviously be a fairly large number of sets 

 of quadruplets in which both parents had anomalies. Some sets 

 show clearly this biparental influence, but in many cases it is 

 impossible to decide whether the condition is inherited from the 

 mother alone or is of biparental origin. 



2. Another source of error in presenting a pictorial tabulation 

 of the localization of these minute elements is the result of a 

 somewhat arbitrary method of determining the middle of a band, 

 for although I have chosen to locate the middle by dividing the 

 scutes into equal numbers on right and left sides, I feel sure that 

 the arithmetical middle does not always correspond to the mor- 

 phological middle. There are definite indications in many cases 

 that there are more scutes on one side of the median dorsal line 

 than on the other, in which instances the arithmetical middle is 

 obviously not median. This condition is probably due to the 

 fact that when two parents with decidedly different scute 

 counts mate we may get the maternal number in one half band 

 and the paternal in the other. The middle point therefore is not 

 a very favorable landmark for scute localization but it seems 

 necessary to use it in order to indicate unilateral symmetry re- 

 versals. Localization from the lateral margins of the bands is 

 much safer than localization from the middle and it is quite obvious 

 that laterally placed scutes show much closer correspondence in 

 position than do those near the middle. 



3. Another factor that shows the inadequacy of the numerical 

 localization method inheres in the fact that different bands vary 

 greatly in number of scutes, ranging from 57 to 70 in the present 

 collection. Now a scute that is pictured as being 5 scutes from 

 the margin in a band of 57 scutes is morphologically farther from 

 the margin than a scute located 5 places from the margin of a 

 band of 70 scutes. So when we are comparing the locality of the 



