HEREDITY AND ORGANIC SYMMETRY IN 

 ARMADILLO QUADRUPLETS. 



II. MODE OF INHERITANCE OF DOUBLE SCUTES AND A DIS- 

 CUSSION OF ORGANIC SYMMETRY. 



H. H. NEWMAN. 



A. GENERAL STATEMENT. 



This paper is in continuation of a study published under the 

 same general title in July, 1915. In that paper the inheritance 

 and distribution among quadruplets of more or less extensive 

 band anomalies were dealt with. All anomalies involving the 

 presence of two or more consecutive double scutes either in 

 mother or in one or more offspring of a polyembryonic set were 

 considered as band anomalies. There remained numerous cases 

 of inherited anomalies so minute as to involve only isolated double 

 scutes in parent and in offspring. A detailed study of the in- 

 heritance and of the symmetrical or asymmetrical distribution 

 of these double scutes among the fetuses of quadruplet sets forms 

 the subject matter of the present contribution. 



In order to have a compact and truly homogeneous group to 

 work with, I have decided to confine my study to collections C 

 and K, omitting several small collections, the data of which are 

 not so complete. In the C and K collection there are 140 sets of 

 quadruplets which are sufficiently advanced to show every detail 

 of the scute pattern. The shells of the mothers of all these sets 

 are preserved and have been carefully scutinized for anomalies. 

 Such shells as were badly worn or damaged had to be excluded 

 from the present study together with the associated offspring. 

 A study of 140 sets should reveal the conditions typical for the 

 species, since we have a collection of 700 individuals. Of the 

 140 sets of quadruplets 73 are female and 67 male. This dis- 

 crepancy between the sexes is due to two circumstances, first 

 that three sets of fetuses, in which the sex was obviously male, 

 were too small to count, the mothers in all cases being normal, 



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