-f 



AliTIFICIAL PROPAGATION OF OYSTERS. 749 



u the edge of the upper plate. Each drop carried over iiiauy 

 k and after the lower j)late began to till and inspections of the 

 % showed a diminution in the number of embryos, the plate con- 



the eggs was removed and either the- contents thrown away, 

 i;ond resting period allowed in order that another lot might de- 

 ia which case the operation was repeated. In using the funnel it 

 lij^ended over a jar or large beaker, and after the emljryos began 

 |m to the surface the air jet was reduced or cut off, and in the 

 Lstance, a minute jet of water substituted. Originally the fuu- 

 i, onl}' half filled, and the water jet being small occupied one or 

 Ins in filling the remaining space and at the same time kept up a 

 jjaiovement among the eggs. Care was necessary that the unde- 

 I eggs should not be thrown very near the surface so as to iuter- 

 th the swimming embryos or become mixed with them. After 

 jnel filled, the water jet caused a gentle overflow into the beaker, 

 "loverflow was continued as long as the number of embryos i)ass- 

 j^r justified it. 



jsketches show the manner in which we arranged this very simple 

 Itus, though it is hardly of so complex a character as to require 

 jLtion; they may, however, be of assistance to others, and perhaps 

 to the germ of a method or appliance that will produce valuable 



j|r the swimming embryos have been separated from the unde- 

 id eggs, their subsequent treatment involves the consideration of 

 aatural conditions, all of which have more or less infiuence upon 

 bcess of the experiment; but as they also exert an influence upon 

 fvolopment of the eggs during segmentation, and as the life of 

 flbryo does not, apparently, dei^end upon manipulation, I have 

 ered it best to allude to the effect of varying natural influences, 

 Itely from those due merely to management of apparatus or gen- 

 ii fluids. 



liunce of iemperature. — While I am not prepared to say that the 

 Irature of the water during the develoi)ment of egg or embryo is 

 i)st important consideration, and while I do not wish to be under- 

 ias stating these following influences in the order of their relative 

 irance, yet, so far as my experience goes, I am inclined to think 

 lie extent of the influence of temperature is sufficient to cause it 

 k at the head of the various causes affecting the success of the 

 ments. It is scarcely possible in an investigation conducted 

 X so many and various afiecting conditions, to eliminate sufficiently 

 fluence of all others so that one may be able to speak definitely as 

 remaining cause for success or failure; but after considerable ex- 

 ice 1 feel justified in coming to the following conclusions with ref- 

 J to the effect of temperature. 



IChe condition of the eggs is not only dependent ui)on the depth 

 ter (or temperature) from which the parent is derived, originally, 



