STUDIES ON THE MAMMARY (iLAND 



361 



less I'roin-a general type; and it thus becomes necessary in some 

 places to make the description somewhat detailed. This de- 

 scription is given later under "Growth of the ducts." 



Fig. 3 Internal view of a wax model reconstructed from the left second tho- 

 racic gland of a newborn albino rat. X 40. a, anastomosis; c, collateral duct; 

 ep.in., epithelial ingrowth of nipple; e.b., end-bud; I. p., lateral process; p.d., pri- 

 mary duct; s.d., secondary duct; t.d., tertiary duct; tr.d., terminal duct. 



In figures 3 to 6 (from wax reconstructions of the newborn) 

 the inti'a-epidermal portion of the primary duct is not visible, 



