VIIl] 



THE SEGMENTATION OF THE EGG 



377 



considered) is responsible for many inaccurate or incomplete 

 representations of the mutual arrangement of aggregated cells. 

 In the accompanying series of figures (Figs. 160-167) I have 



Fig. 160. Segmenting egg 

 of Trochus. (After Robert. ) 



Fig. 161. Two views of segmenting egg of Cynthia 

 partita. (After Conklin.) 



Fig. 162. (a) Section of apical cone of Salvinia. (After Pringslieim*.) 

 (b) Diagram of probable actual arrangement. 



163. Egg of Pyrosoma. 

 (After Korotneff). 



Fig. 164. Egg of Echinufi, segmenting 

 under pressure. (After Driesch.) 



* Tliis, like many similar figures, is manifestly drawn under the influence of 

 Sachs's theoretical views, or assumptions, regarding orthogonal trajectories, coaxial 

 circles, confocal eUipses, etc. 



