H. M. FiTCHs 277 



1. Experiments luith Cioiiu intestinalis. 



In Exps. 1 and 2 (Table XVI), eggs from three individuals' were 

 kept in 3 — 4 times their volume oi water for 5} hours, to obtain the 

 " egg-water." Given amounts of sperm-suspension were dropped into 



(1) 10 drops of plain water, (2) 10 drops of the egg- water. 10 cc. water 

 was then added to (1) and (2), and they were poured on to appi-oximately 

 equal amounts of eggs from a given individual. 



In Exp. 3, eggs from several individuals lay in 3 — 4 times their 

 volume of water for two hours. The rest of the treatment was the same 

 as in Exps. 1 and 2. 



For Exp. 4 an individual was found with an exceptionally large 

 number of eggs. Some of these were allowed to stand in 10 times 

 their own volume of water for two hours to obtain the egg- water. Given 

 amounts of sperm-suspension were dropped into (1) 1 cc. of water, 



(2) 1 cc. of egg-water. (1) and (2) were then poured on to equal 

 amounts of eggs from the same individual from which the egg-water 

 had been obtained. 



The results of the experiments are given in Table XVI. 



TABLE XVI. 



Plain water Egg-water 



n , , „ »r- 1 . I 3 drops sperm ... 2 11 



Exp. 1. Alb, Mixed egg-water -' „ ,„ 



( o ,, ,,-,.. o io 



TH 1 ^;j «»• 3 i I 2 di'ops sperm ... 



Exp. 2. C/rf, Mixed egg-water • , 



T-. o r, 1 ■ .»•• -1 X I 2 drops sperm ... 2 5 



Exp. 3. EU, Mixed egg-water -j ^ ^ ^ ^.^ ^^ 



Exp. 4. Glk, G egg-water ... ^^ ^'"J' ^'-"^ ' • ^J ^J 



These experiments show that for Ciona, water in which eggs have 

 lain has the same stimulating effect on spermatozoa that artificial 

 egg-extracts have. 



2. Experiment with Arbacia pustulosa. 



This experiment was made on exactly the same lines as those just 

 described with Ciona. Egg-water experiments are, however, much more 

 easily made with Echinodejms than with Ciona, since a much greater 

 volume of eggs can be obtained, and hence more water containing the 

 egg-secretions for experimentation. 



' I need hardly repeat that as in all other experiments recorded in this paper, controls 

 were kept. Unfertilized samples of all the eggs used for egg-waters were put on one side 

 and afterwards examined to see that none had segmented. 



