534 ^- H- A7^^'U77zrt« 



like {H§), H hybrids like (Ad), M hybrids between {m6) and [my), 

 and M pures between (mj) and {m6). H pure highly pigmented 

 and with the following heart rates: 58, 58, 74, 62, 48, 70, 42, 75, 

 70,56. Average 61.3. // hybrids no pigment and with the follow- 

 ing heart rates: 74, 42, 66, 48, 76, 48, 64, 60, 108, 72. Average 

 64.8. M hybrids no pigment, following heart rates: 60, 48, 62,60, 

 60, 52, 60, 56, 64 (one not yet beating). Average, exclusive of 

 the last, 59. M pure no pigment and no heart-beat. 

 At 84 hours: Heart rates as follows: 



H pure — 78, 78, 84, 56, 78, 72, 72, 74, 80, 82. Average 



75-4- 

 H hybrid — 84, 74, 74, 80, 90, 78, 78, 94, 92, 94. Average 



83.8. 

 M hybrid— 88, 80, 96, 84, 86, 92, 90, 88, 84, 86. Average 



87.4. 

 M. pure — 72, 62, 66, 66, 64, 60, 68, 72, 64, 60. Average 



65.4. 



At 108 hours: H hybrids seemed somewhat larger than H 

 pures but were much more lightly pigmented. Heart rates as 

 follows : 



H pure — 100, 108, 112, 100, 104, 112, no, 102, 108, 100. 



Average 105.6. 

 i^ hybrid — 116, 116, 140, 116, 112, 140, 142, 132, 152, 136. 



Average 130. 

 M hybrid — 120, 128, 120, 124, 124,124,36,140,136, 128. 



Average 118. 

 M pure — 132, 128, 132, 140, 144, 126, 132, 124, 140, 134. 



Average 133-2. 



Other stages up to hatching not markedly different from Series 

 I. H pures hatched out on the average three days earlier than 

 H hybrids. M hybrids did not hatch at all, but reached almost a 

 uniform size, about equal to that of H pure on hatching. All 

 M pures hatched in an average of about twenty-two days. 



Series ^, June 25, igoy. This series was started with unusual 

 care and was followed for five days under close observation. It 



