ORGANIC SYMMETRY IN ARMADILLO QUADRUPLETS. 195 



Set K 70 (p. 1 85) . Mother has scute 6 to right of middle double 

 in bands 2 and 3. Fetus I. has scute 3 from the left margin double 

 in both bands 4 and 6, also in bands I and 7. Fetus IV. has in 

 bands 2 and 6 the same double scutes as fetus I. has in bands I 

 and 7, but there is a symmetry reversal in the half bands. There 

 seems to be a strong tendency for the offspring in this set to 

 inherit the vertical reduplication of the mother. 



H. Transverse Reduplication in a Single Band. Here are 

 included cases in which two or more double scutes occur close 

 together but not contiguous in the same band. Such cases are 

 probably in the nature of interrupted band anomalies. Examples 

 may be seen in sets K 18, K 10, K 43, K 56. There are as many 

 more cases in sets with normal mothers that are shown in the 

 appendix. 



The interpretations offered in the above analysis may be open 

 to objection in certain cases but there can be no controversy as 

 to the nature of the great majority of cases. There is strong 

 evidence of much mirror-imaging between pairs and between 

 individuals of a pair and there are numerous cases of half-band 

 reversals quite like those occasional reversals of finger-print 

 patterns described for duplicate human twins by Wilder, and 

 which Bateson believes to be evidences of a former system of 

 symmetry common to the two individuals before the separation 

 of their primordia. If these rare and vestigial reversals in du- 

 plicate human twins are to receive the above interpretation, we 

 should feel no hesitancy about a similar interpretation of the 

 quite frequent occurrence of symmetry reversals in armadillo 

 quadruplets. 



C. DISCUSSION AND CONCLUSIONS. 

 i. The Problems of Inheritance and Segregation. 



(a) The Exceptional and Unique Character of the Material. 

 No other animal that I know of is so beautifully adapted for 

 the study of specific and individual variability as is the armadillo. 

 The strikingly diagrammatic arrangement of the integument into 

 the five armor shields furnishes an unusual opportunity for 

 accurate enumeration of units and for a study of inter- and 

 intra-individual correlation. These characters, moreover, are 



