NIPPLE DEVELOPMENT IN SQUIRREL 



125 



are often developed, which always originate 

 between the pectoral and the first abdominal 

 priraordia (Fig. 43, *). Finally, when fission is 

 ended, the smaller shift more and more in a 



Fig. 43. Nipple Development of "Sciukus 



vulgaris." 



p, Primary-primordium of pectoral nipple ; *, prinMi-y-primordium of 

 supeniumeraiy; <H. primary -primordmin of first abdominal 

 nipple ; a^, primary-primordium of second abdominal nipple. 



medioventral direction away from the larger 

 ones (Fig. 44). 



One understands from this how the view 

 arose that in the squirrel double nipple rows 

 exist. It must be noted, however, that the 

 two caudal pairs of nipples are not doubled. 



