SECT. 2] AND WEIGHT 



Table 64. Gestation time and incubation time (cont. 



Crustacea 



Species 

 Wa.teT-t\ea. (Daphnia pulex) 

 Lobster 

 Amphipod {Gammarus chevreuxi) ... 



489 



Incubation time 



75-85 hours 



ID months 



8-9 days 



Insects 



Cockroach (Periplaneta orientalis) ... ... 75 days 



Tent-caterpillar moth {Malacosoma americana) 9-5 months 



Sarcophagidae ... ... ... ... Less than a day 



y{ous,e ^y {Musca domestica) ... ... 8-12 hours 



Lepidoptera ... ... ... ... Several months 



Phasmidae ... ... ... ... 2 years 



Ant {Aphaenogaster fulva) ... ... ... 17-22 days 



,, {Myrmica rubra) ... ... ... 23-24 ,, 



Dragonflies ... ... ... ... 3 weeks 



Oriental peach-moth {Laspeyresia molesta) 4 days 



Butterfly [Diacrisia virgimca) ... ... 5-5 ,, 



^■win&-\ouse {Haematopinus sui) ... ... 14 ,, 



Beet Leafhopper {Eutettix tenellus) ... 10-50 days 



Stonefly {Perlodes mortoni) 91 days 



,, (Ptrla carlukiana) ... ... ... 59 ,, 



,, {Nephelopteryx nebulosa) ... ... 20 ,, 



Mayky {Siphlurus armatus) 15 weeks 



,, [Ecdyurus venosus) ... ... ... 15 days 



Molluscs 



West African land-snail {Achatina variegata) 

 Periwinkle {Littorina littorea) 



Worms 



Roundworm {Ankylostoma duodenale) 



40-60 days 

 6 days 



-3 days 



Investigator 

 Ramult 



Allen 



Ford & Huxley 



Zabinski 



Rudolfs 



Imms 



Fielde 



Needham 



Snapp & Swingle 



Johannsen 



Weber 



Severin 



Percival &Whitehead 



Pycraft 

 Haves 



Looss 



Table 65. Time-relations of early development. 



Amphibians 



Wilson's figures (15° C.) 



Species 



Salamander {Amblystoma punctata) 

 Frog {Rana temporaria) ... 

 Small wood-frog {Chorophilus tri- 

 serratus) 



Hertwig's figures (14° C.) 



Fertili- 

 sation 

 to first 

 cleavage 

 (hrs.) 



10 

 35 

 1-5 



Cleavage 

 periods 

 (min.) 



1st 



no 

 75 

 30 



2nd 



100 

 60 

 40 



Rana temporaria 

 Gastrulation 



Formation of medullary plate 

 Closure of medullary folds 

 Appearance of tail-bud 

 Appearance of tail and gills 

 Appearance of tail-fin 

 Beginning of operculum ... 



Gastru- 

 lation (hrs.) 



3rd 



100 

 50 

 30 



Begin- 

 ning 



60 



42 



End 



78 

 50 

 13 



Days after 

 fertilisation 



1-3 



4-2 



5-5 



6-8 



8-6 

 no 

 13-4 



Appear- 

 ance of 



external 

 gills 

 (days) 



19 

 14 



35 



Adult 

 (days) 



100 

 70 

 30 



