The Process of Heredity c^c 



then became necessary to be absent from the laboratory for a few 

 days. After returning the experiment was not followed in detail, 

 but what records were taken show a striking resemblance to con- 

 ditions seen in Series i. The figures made with camera lucida 

 during the first five days might almost be substituted, stage for 

 stage, for the figures in the table used for Series i. 



Series 5, June ig, igo6. Fresh adults of both species, at the 

 height of spawning season, used. Over 100 specimens of each 

 of the four strains. 



At 52 hours: H pure lens formed and many somites, resembling 

 {H4). H hybrid no lens and few somites, slightly more advanced 

 than (A^). M hybrids blastopore nearly closed and optic lobes 

 beginning to appear. M pure blastopore still wide open and no 

 optic lobes. 



At 72 hours: H pures somewhat more advanced than {Hj). 

 Pigment on body and yolk and hearts beating strongly. H hybrid 

 about like {m6). A few have very slow and feeble heart-beat. 

 No pigment. M hybrid between {H^) and (H/f.). Lenses and 

 optic cups just forming. Auditory vesicles faintly defined. No 

 heart-beat and no pigment. M pures less advanced than M hybrid 

 about like (i-f 5), scarcely any trace of lens formation, no auditory 

 vesicles, and no pigment. 



At 96 hours: H pures heavily pigmented. Hearts vigorously 

 beating. Embryos wriggling within the egg membrane. H 

 hybrids weakly pigmented in a few specimens. Heart-beat on the 

 average more vigorous and rapid than in H pures. M hybrids 

 heart-beat vigorous; no pigment; embryo wriggling. M pures, 

 heart-beats beginning to be established in a few specimens; no 

 pigment and no wriggling. 



At 5 days: H pures very deeply pigmented with dark brown 

 chromatophores; average heart rate often, 109.7. H hybrid not 

 nearly so heavily pigmented as H pure; heart rate often, 113. M 

 hybrid as heavily pigmented as H hybrid ; average heart rate of ten, 

 109. M pure, no pigment on body; extremely faint pigment on 

 yolk; average heart rate often, 99. 



Other stages up to hatching were substantially like Series I. 

 except that the series as a whole developed more slowly; the H 



