

190 



MERISTIC VARIATION. 



[part I. 



there is generally if not always a disturbance in the paired arrange- 

 *163. ment. A simple case of this kind occurring in the dog is represented 

 in Fig. 33. The animal is a male bulldog lately in my possession. 

 On the right side there are four nipples, while on the left there 

 are five. The most anterior on each side stand almost at the same 

 level on the thorax. The second on each side are almost at the 

 same distance below them, that on the left side being ^ in. higher. 

 Similarly the most posterior nipples stand on each side at almost 

 exactly the same level on the sheath of the. penis, the total length 

 from the first to the last nipple on each side being practically the 

 same. On the left however there are two nipples placed between 

 the second and the last, but on the right there is only one. This 

 one nipple stands at a level not far from the middle between the 

 3rd and 4th of the other side, making as it were a complement to 

 or balance with them. 

 *164. Thirty-five young pigs examined with regard to these questions 

 gave the following results. They belonged to five litters (30 pure- 

 bred Tam worths ; 5 cross-bred, out of Berkshire sow, sire unknown). 

 These pigs were all quite young, about a fortnight old, and conse- 

 quently there was no displacement due to functional development 

 of the glands. 



MammyE. 



Right. Left. Pigs. 



A. 6 — G regularly arranged in pairs 3 



B. 7 — 7 ditto 10 



C. 7 — 7 ditto 5th rudimentary 1 



D. 8 — 8 ditto 4th rudimentary 3 



E. 7 — 8 all paired exc. 1. 4th rudimentary '. 2 



F. 7 — 8 1. 4th rudimentary, 1. 3rd and 5th displaced... 1 



G. 7 — 8 rt. 2nd balances 1. 2nd and 3rd 1 



H. 8 — 71. 2nd balances rt. 2nd and 3rd 1 



I. 8 — 7 1. 3rd balances rt. 3rd and 4th 1 



K. 6 — 7 rt. 1st balances 1. 1st and 2nd 1 



L. 6 — 7 1. 2nd rudimentary 1. 1st and 3rd displaced... 1 



M. 6 — 7 all paired exc. 1. 4th rudimentary 1 



N. 7 — 7 altogether irregular 4 



O. 6 — 6 ditto 2 



P. 7 — G ditto 1 



Q. 7 — 8 ditto 1 



R. 8 — 7 ditto 1 



Total 35 



The animals in groups D and E, except one of the latter, be- 

 longed to the same litter. In them a small rudimentary nipple 

 stood between the 3rd and 5th, but the latter were not spaced out 

 for it, being no further apart than any of the others. The measure- 



