-- 



Mi:i:i-TH VARIATION. 



[PART i. 



mammary Variaii'-n in other mammals. In connexion with the 

 Mm it in iv In- mentioned that supernumerary mamma 

 he|,i\v and internal to the normal ones has been seen in Macacus 

 and in Cercopithecus patas, SUTTOV J. B., Intern. Jour, of Med. 

 1889 \< VII. pp. !'>'! and 2.~>:> ; in the Orang-utan, OWEN, 

 i. A iii. p. TMI. In many mammals the number of the 

 - i- very inc"ii<tant even within the limits of species and 

 tin- : n in such cases deductions may be drawn which 



are at one.- in-truetive as to the nature of mammary Variation 

 and lia\<- an -i pplica: ion to the morphology of Meristic Series in 

 i M these 1 shall give examples taken from three species. 



The tir.-t i- that "f the cow's udder. Normally the cow has 

 f..iir beats "f alioiit eijual size. Not nnfrequently there are six 

 tent-, of which four an- large and may be said in the usual parlance 

 to In- the " normal " ones, and two are small and placed posteriorly 

 to the ft h-r-. A case of this kind is shewn in Fig. 32, II. Commonly 

 tin - ,e no milk, but in many cases they have been 



kii-iun bo do so. Their -ixe and position vary greatly ; sometimes 

 the\ are placeil near the other teats as shewn in the figure, but I 

 ha\. seen them very hi^h up, almost in the fold between the 

 udder ami the thi^h-. 



Very frequently, however, there is only one extra teat making 

 tr. e in all, .sin-h an extra teat being so far as I know, always on 



I' s,ip. ilium. n t\vn iirjiWs. I. The third teat is completely 



. I'Ht IMI the ri^'lit si,lr i* uiiiti'il with tin' second. (Tin- 

 lh- t\\" is iiir.ii ri-.-tly rr]>ri"i.'iit.'il ;is u sharji line; there was no such 

 t ileiiiui-cati,.|i ; die ^kiu heinu' MTV slightly ile]iri'sseil in this place.) 

 II. ! the thinl 1'iiir Imili c.nni'leti , . - pal 



