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PROCEEDINGS OF THE AMERICAN ACADEMY. 



Appendix. 



Records of 1000 litters of unborn pigs showing the relative position 

 of the pig in the uterus, its sex, and the number and arrangement of 

 its nipples. The table begins with litters of one pig and proceeds in 

 sequence to the largest litter, one of fifteen. The litters are numbered 

 from 1 to 1000. The vertical heavy line indicates the line of separa- 

 tion between the right and left horns of the uterus; the records at the 

 reader's left from this line represent the pigs in the left horn of the 

 uterus, at the reader's right in the right horn. Each pig is repre- 

 sented by a letter and two figures: m indicating male, f indicating 

 female, and the figures indicating the numbers of nipples on the left 

 and on the right side of the pig. The sides of the pig correspond to 

 the reader's right and left. When the sex letter is Roman, the ar- 

 rangement of the nipples was regular (p. 402), when italic, it was ir- 

 regular. Thus m 76 indicate a male pig with 7 nipples on the left and 

 6 on the right arranged irregularly, and f 76 indicates a female pig with 

 the same numbers of nipples on each side as the male, but regularly 

 arranged. The records for each litter, occupying a single line, form a 

 series corresponding to that of the pigs in the uterus, in that the ex- 

 treme left-hand record was taken from the pig nearest the left ovary, 

 the extreme right from the one nearest the right ovary. 



