Figure 36. The development of Clepsine (by Grube) . 



a — fertilized ovum, b— ovum on which the white disk with grey 

 ring appeared, c— first fissure; the white disk is present 

 near it. d — yolk globule, divided into four parts, e— yolk 

 globule, divided by six transverse fissures; the polar field 

 increases as the surrounded globular segments decrease in size 

 due to the loss of albumen (molecular) mass used for the forma- 

 tion of WANDUNGSBALLEN on the active pole, f — -the same stage, 

 globules of division from the lower side; on the inactive pole 

 the polar field is seen, i.e. the surface of the seventh segment, 

 separated from the other round fissures, g — somewhat later 

 stage, view from, above; the number of WANDUNGSBALLEN increas- 

 ing, they then form a small disk which can be regarded as a 

 rudiment (KEIM). h — WANDUNGSBALLEN increase in number and 

 occupy a great area, forming the embryonic field, i — the view 

 of the abdominal shaft from behind; they move so far apart that 

 they envelop the yolk globule by a ring . j— the abdominal shaft 

 from the side; on the posterior end of each, three whitish 

 globules are present, k — the abdominal shafts unite together. 



524 



