88 



PROCEEDINGS OF THE AMERICAN ACADEMY. 



The reduction in the number of glands takes place from one end, — 

 the distal end of the series. Generally, where there are only two or 

 three glands these occur high up and the normal diatance apart. Rarely, 

 however, the reduction is brought about in part by the failure to de- 

 velop in the middle of the series while glands develop near the extremes, 

 so that there is a broad hiatus in the series. 



Since the proximal end of the series is that at which glands are most 

 likely to be formed, and since they tend to be produced more abundantly 

 there, this end, which occupies the region of the upper wrist, is to be 

 considered as the source of the moi'phogenic impulses which give rise to 

 the glands. Sometimes the embryonic Anlage does not develop beyond 

 this point ; sometimes, on the other hand, it develops along the whole 

 extent of the wrist in one row, and even forms an accessory "lateral" 

 row. 



The total number of swine examined was, as stated, 4,000 ; of which 

 2,000 were males and 2,000 females. The total number of fore legs 

 examined was, accordingly, 8,000 ; 4,000 left and 4,000 right. All of 

 the observations fall, consequently, into four grovxps of 2,000 cases each; 

 namely, male right, male left, female I'ight, female left. These four 

 groups will be considered, for the most part, separately. 



We first determined how many legs in each of these classes had no 

 glands, one gland, two glands, and so on. The results are given in the 



following table. 



TABLE I. 



