339 



Fig. 1. 



Fig. 2. 



Fig. 3 



Fig. 1. Section of nucleus of young ovum (^|^ mm in diameter), showing masses 

 of chromatin granules in the caryolymph, and the nucleolus which has apparently caused 

 a distention of the nuclear membrane by the pressure of its own weight. F^rom the ovary 

 of a lobster captured July 18th, 1894 ; external eggs recently hatched, 'y^ 248. 



The arrow in Figs 1 — 4 shows the direction in which the force of gravity was 

 exerted. 



Fig. 2. Section of nucleus of developing ovum, somewhat larger than the one 

 represented by Fig. 1, showing nuclear membrane shrunken away from cytoplasm and 

 yolk, and granular chromatin as before, with no trace of a nuclear network. )><^ 248. 



Fig. 3. Part of transverse section of ovary of lobster, hardened with the ventral 

 surface uppermost. The nuclei have fallen towards the dorsal side, and lie in contact 

 with the wall of the nucleus. From the same as Fig. 1. ^ 50. 



Fig. 4. Part of transverse section of ovary of lobster, hardened with its dorsal 

 surface uppermost. The nucleoli lie against the ventral surface of the nucleus. From 

 same as Figs. 1 and 3. X ^*^- 



22* 



