MODES OF INHERITANCE IN HYBKID.S 



479 



TABLK 12 

 Sfioiring piqinenl chdrdiiiTs in hybrids between F. iliaplui/i us (dhI F. heleroriiliis 



F. HETEBOCLITUS 9 X F. DIAPHANUS cf 



1 



F. DIAPHANUS 9 X F. HBTEROCLITDS cf 



Rod yolk c. intermediate in coloi- 

 liotwoen tlie maternal red-brown 

 and the paternal brick rvd (fis- 

 33) 



Black yolk c. like F. dia])hanu.s in 

 size and branching, but show a 

 tendency to fuse as in F. hetero- 

 clitus 



Both maternal and ])aternal t>'pes 

 of black head c. i)resent ; the ma- 

 ternal ty])e ajjpears first at about 

 3 days, followed by the paternal 

 type in about 4 days (the first 

 crop of Bancroft); each type has 

 the characteristics of the ])ure 

 species (fig. 24) 



Three rows of red-brown c. on sides 

 of body, intermediate in color 

 between those of two s])ecies 



Black yolk c. larger and darker on 

 side o])posite embryo than else- 

 where, as in maternal species 



Lat(>ral line with number of black 

 c. intermediate between two 

 species 



First yolk c. appear as early as in 

 F. heteroclitus; time not inter- 

 mediate 



Red c. of head intermediate in color 

 between two species 



Fusion in the F. heteroclitus type 

 of black c., l)ut the F. diaphanus 

 type isolated (fig. 24) 



Same as reciprocal cross, but a little 

 smaller on the average (fig. 34) 



Same as reciprocal cross except that 

 the type of c. is again almost pure 

 F. diaphanus and there is scarcely 

 a trace of fusion 



All black head c. of the F. diaphanus 

 type, but there is much fusion as 

 in F. heteroclitus (fig. 25) 



Same as recii)rocal cross except that 



there are fewer c. to the row, the 



body being shorter 

 Black yolk c. less numerous on side 



opposite embryo than elsewhere; 



this is not like either parent 

 Same as reciprocal cross 



Same as recipi'ocal cross 



Same as reciprocal cross 



All black c. of the V. diaphanus type 

 •and fused extensively (fig. 25) 



THE JOIRN-AI, OF EXPERIMEXrAL ZOOLOGY, VO' . 16, NO. 4 



