GERM CELLS AND THEIR FORMATION 



91 



protoplasm, or by the collection of various pigments and dif- 



ferently colored granules, or by forms 



of deutoplasmic materials other than 



yolk, or in various other ways. The 



disposition of these substances usu- 



ally expresses, incompletely, how- 



ever, an underlying organization or 



morphology of the egg substance as f 



a whole, which is considered a fun- 



damental structure of the egg as a 



specific organism. This organiza- 



tion is practically always polar, i.e., 



disposed symmetrically with refer- 



ence to one chief axis (Von Baer), 



and in the eggs of most bilateral d 



animals examined, it is bilateral also 



(Roux, Van Beneden). In some 



way this morphology of the egg is 



related to the morphology of the 



embryo developed from the egg, and 



hence is called its promorphology. 



This promorphology is better 

 termed organization, for it is not only 

 grossly material, but also dynamic, 

 i.e., energetic, depending upon chem- 

 ical and physical arrangements not 



often visible directly. The extent drawing of a median section 

 i , -, , through the fertilized egg of the 



and nature of this organization are fly> Musca . From Korscheit 



Often Obscure, but this, and the and Heider, after Henking and 



Blochmann. ch, chonon; d, 

 nuclear Structure of the OVUm, are flattened dorsal side of the egg; 



FIG. 47. Semidiagrammatic 



probably its most important char- 



acteristicS, for together these deter- traded through the micropyle; 



.. . , , k, cortical layer; m, micropyle; 



mine the COUrse Of its development this also marks the anterior end 



as a Specific Creature. f ^e egg; p, egg and sperm 



r _ e pronuclei in process of fusion ; r, 



Polarity is One expression Of this polar bodies; v, ventral side of 



organization. The polarity of the 



fully formed ovum is related to the polarity of the egg cell 



