No. 572] 



PATTERN DEVELOPMENT 



475 



under side of the specimens. In the large coastal race of 

 mink found from southern Maine to the Carolina* ( .1/. r. 

 lutreocephalus), the entire pelage is usually brown, ex- 

 cept for the chin which is white. Occasional white marks 

 are present in some specimens along the mid-ventral 

 line of the throat and chest, and between the hind legs. 

 In the smaller typical 31. vison of northern Xew England 

 northward the white marking is apt to be more extensive, 

 and in no two individuals exactly alike. The diagrams 

 show the ventral markings of a few specimens from New 

 England and Nova Scotia. In Fig. 43 the amount of 

 white is very small. The chin spot, which represents the 

 beginning of a break between the two ear patches at their 

 antero-ventral extremity, is always present and has be- 

 come now a fixed mark of the species, though variable in 

 extent. A slight break in the center of the chest shows 

 where the two shoulder patches have failed to meet, and 

 a white spot at the anal region indicates a like restriction 

 of the rump patches. Similar spots appear mid-vent rally 

 in Fig. 44, with the addition of a few white hairs, medially 

 at the upper throat, where the ear and neck patches join, 

 and a few more on the lower throat at the line of union 

 of the neck patches of opposite sides. In Figs. 45 and 46 

 no break is present on the abdomen, but in the former 

 figure, a large transverse break has appeared on the 

 upper throat where the ear patches fail to unite with the 

 neck patches and with each other, and a median line runs 

 forward to join the white of the chin, showing the greater 

 restriction of the ear patches ventrally. An imperfect 

 separation of these patches along the center of the throat 

 has taken place in Fig. 47, and a more considerable break 

 occurs in the same place in Fig. 46. In the Pacific Coast 

 mink (Mustela rison energiunenos) a well-developed 

 white patch on the chest is rather characteristic, some- 

 what larger than in Fig. 45. This is due to the ventral 

 restriction of the shoulder patches which fail to meet 

 below. In Fig. 46 this white area is seen with a tongue 

 extending upon the center of the lower throat, and on to 



