334 RALPH S. LILLIE. 



1 he characteristics and behavior of the eggs from tlu-sr three lots were respec- 

 tively a- follow-: 



LOT A. The great majority oi these eggs fail to maturate. A small proportion 

 undergo apparently normal maturation 



Unfertilized Eggs. 22 hours after removal almost all of the mature eggs show 

 the typical opaque and coagulated protoplasm; i. e., post-maturational cytolysis 

 appears normal. 



Fertilized Eggs. Condition ca. 20 hours after fertilization. 



1. Untreated (Control) Eggs. Many of the immature eggs have typical fer- 

 tilization membranes; but are otherwise unchanged. The few mature eggs are 

 mostly dead; only one abnormal blastula was found. 



2. Ether-treated Eggs. (a) Exposed i hour 10 minutes. Four or five blastulse 

 are found in some hundred eggs; little difference from control, (b) Exposed .; ' t 

 hours. Little or no improvement over control; a few blastula. 1 as in (a). 



LOT B. Most of these eggs remain immature, but about 20 per cent, undergo 

 apparently normal maturation. 



Unfertilized Eggs. 22 hours after removal from the animals most of the mature 

 eggs are opaque and coagulated, but in many the coagulation is less advanced than 

 in normal eggs, and in some the protoplasm remains semi-translucent. 



Fertilized Eggs. Condition ca. 20 hours after fertilization. 



1. Untreated (Control) Eggs. Almost all of the mature eggs are dead. Many 

 immature eggs have fertilization membranes. Only two abnormal blastulae are 

 found in several hundred eggs. 



2. Ether-treated Eggs. (a) Exposed i hour 10 minutes. Improvement over 

 the control; a large proportion (about one third) of the mature eggs have formed 

 blastulae, many of which have begun to gastrulate. (b) Exposed 3*4, hours. Also 

 shows a marked improvement over the control, but the larva? are fewer and less 

 active than in 20. 



LOT C. In this lot of eggs the majority show normal maturation, though a few 

 remain immature. 



Unfertilized Eggs. After 22 hours in sea-water most of the eggs are more or less 

 coagulated, but the degree of opacity is distinctly less than in normal eggs, and a 

 considerable proportion remain translucent almost like freshly shed eggs. 



Fertilized Eggs. Condition ca. 20 hours after fertilization. 



1. Untreated (Control) Eggs. Nearly all are dead. Most have membranes and 

 show evidence of having cleaved or fragmented, but many have failed to cleave or 

 even to form membranes. A small proportion of eggs have formed larvae some of 

 which appear normal: the larvae though few are more numerous than in the controls 

 of A and B. 



2. Ether-treated Eggs. (a) Exposed i hour 10 minutes. Striking contrast to 

 control. Almost all of the mature eggs have formed active larvae, many in tin- 

 early gastrula stage and swimming at the surface of the water, (b) Exposed .i ' i 

 hours. Here also the majority of eggs form larva;, but these are largely abnormal, 

 and relatively few gastrula? or surface swimmers are present. 



The power of development after fertili/ation is thus ^really 

 increased after ether-treatment in Lots B and C, l>ut not in Lot A . 

 The mature eggs of Lots B and Cshow marked delay in the post- 

 maturational cytolysis; in Lot C this delay is greater, and the 



