PLATE 1 



EXPLANATION OF FIGURES 



7 Drawn from a cleared preparation (internal view) of an albino rat one 

 week old (weight 8.5 grams) to show distribution and relations of ducts of left 

 abdominal gland (A); left first inguinal gland (5); and left second inguinal gland 

 (C). X 5. A.n., abdominal nipple; Im.I, I.n.2, 1st and 2d inguinal nipples; p.d., 

 primary duct; s.d., secondary duct; t.d., tertiary duct; tr.d., terminal duct; e.b., 

 end-bud; c, collateral duct. 



8 Same as figure 7, but from an albino rat two weeks old (weight 15.5 grams). 

 X 5. 



9 Same as figure 7, but from an albino rat three weeks old (weight 30 grams). 

 X 5. 



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