Memoirs National Academy of Sciences, XII. 



, , Second Memoir, PI. 60, 



DIAGRAM SHOWING MENDELIAN INHERITANCE IN THE GENUS lo. (HYPOTHETICAL.) 



U 



Smooth y^ Spinost 



Parents— Smooth (o), and Spinose (s), crossed. 



^44^ 



First Generation, Fi, sliowing all smooth shelled progeny, and the dominance of smoolhn 



^4 *♦ ♦♦ H 



Second Generation, Fj, showing results of crossing in pairs, 

 the Fi generation: 1 are spinose and J are smooth, and 

 thus show the Mendelian ratio. 



Extracted dominants 



,^#^ H^i HH HH 



HH HH ^^H HH 



Third Generation. Fj, showing the proportion of 

 dominant (1) and recessives (i). and the Men- 

 deilan ratio in the progeny of the dominant 



s(d) s(r) 



o(r) 0(d) 



s(d) s(r) 



0(r) 0(d) 



s(dl ajsl 



-ToT 0(d) 



s(d) sOl 



1 J 1 1 Pure race of extracted (spinose) r 



Pure race of extracted (smooth) dominants. 



