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42 maps. 



43 



r tial in character, is clearly 

 , middle, and inmost. In 

 ressed oblong, therefore, 



hey are large and diffuse ; 

 the basement membrane, 

 dial sinus, gs, the tissue of 



interspersed with plasma 

 assed through the special- 

 aay be assumed that the 

 lus the closely compacted 



plasma spaces (and capil- 

 These again transfer their 

 o the egg. 



33 D y 



W' . 



10 mm. in diameter). < v, Germinal 

 ;roup of chromosomes ; mgT, limiting 



s region of the zona radial a. In this 



11 vesicle recedes from surface of egg. 

 tic, showing large vacuolcs ; : , zona 

 :en the vesicle and the adjacent tunic 



irently physiological, since 

 icleus of the inmost layer 



is clearly connected with a nucleus ot tne middle layer. In some cases such a rela- 

 tionship is demonstrated by dividing nuclei, which, it may be remarked, exhibit 

 sometimes direct, sometimes indirect division. At the surface of the egg is a sharply 

 marked membrana limitans ; below this, irregular in thickness, a zona radiata, prob- 

 ably homologous with the well-known layer in eggs of other fishes. Below this the 

 egg shows an outer finer layer and an inner coarser or reticular layer, in which 

 large vacuoles frequently occur. At a somewhat later stage (egg measuring about 



