No. 571] PATTERN DEVELOPMENT 



411 



separated from one or the other of them, while tlx- third 

 or lumbar spot has dropped out. On the right side, the 

 first and second divisions are still fused dorsally, but 

 the lumbar division is distinct. The same three divisions 

 are seen in Fig. 35, better developed, whereas in Fig. 42, 

 the two lumbars are present, one on each side, and con- 

 siderably in advance of them, what seem to be the rem- 

 nants of the first division of the side area, the left one of 

 which has further broken up. 



The romp patches show no especial peculiarities, but 

 cover the posterior part of the buttocks and hind legs, 

 and the entire feet and tail. Though frequently the two 

 patches of opposite sides are conjoined medially, they are 

 often, under considerable reduction, well separated. The 

 i>< -•ginning of such a separation appears in Fig. 38, where 

 there is a deep median tongue of white anteriorly, mark- 

 ing the line of union. In Fig. 41 the reduction has pro- 

 gressed still farther so that the two patches are quite sun- 

 dered medially and do not extend to the tail, hi Tig. 40 

 the patch of the left side has become inactive, and that of 

 the right side is small. 



A curious condition not infrequently seen is shown in 

 Fig. 37, in which all the patches are present, but those of 

 the right side are separated from those of the left by a 

 median dorsal white line, showing the distinct bilaterality 

 of these pigment areas. In the figure, the ear patches 

 are so restricted as not to reach the neck patches of 

 their respective sides, the shoulder patches do not extend 

 far on the forelegs, the side patches are reduced ven- 

 trallv, and the rump patches, though in contact with the 

 side patches, do not pigment the tail or extremities of 

 the legs. A further reduction of pigment areas results in 

 Fig. 41, in which the paired centers of neck, side and 

 rump patches still appear. 



The diffuse condition of pigmentation is illustrated in 

 Fig. 36, which is a photograph, inked in. The ear patch 



