BULLETIN OF THE UNITED STATES FISH COMMISSION. 177 



Mr. B. H. Walke, took a large number of eggs and applied the milt. 

 Their attention being drawn to the fishery, however, the eggs were left 

 two or more hours in the water unchanged. They were so much crowded 

 together, and so long unattended, that the imi^regnation was not very 

 good. They were placed into the cones of the United States steamer 

 Lookout, and were only discarded when a more perfect impregnation 

 was attained by Mr. William Hamlin in a separate and perhaps more 

 recent lot of eggs. Mr. Hamlin belonged to the corps of Hon. T. B. 

 Ferguson, 



Some preliminary arrangements will be made next spring toward the 

 propagation of this fine ilsh, by the sub-department of fish and fisheries 

 of Xorth Carolina, which I have the honor to represent. 

 I am, yours, very respectfully, 



S. G. WORTH. 



ON THE RETARDATION OF THE DEVELiOPMEIVT OF THE OVA OF 

 THE SHAD (AtiOSA SAPIDISSIMA), \^ITH OBi^ERVATIOIVS ON THE 

 EGG.F17NGUS AND BACTERIA. 



By JOHi¥ A. RYDER. 



Several series of experiments at different times were undertaken by 

 persons connected with the United. States Fish Commission, having for 

 their object the solution of the following problems: " Is it possible to' 

 lower the temperature of the water in which shad eggs are incubated 

 so as to greatly retard and prolong the i^rocessf "Is it possible to 

 j)rolong the period of incubation so that large quantities of embryo- 

 uized ova may be carried for long distances by land or water so as to 

 effectively stock distant or foreign waters'?" These two queries, I think, 

 clearly state the objects of the experiments, and also tacitly indicate 

 the important results which would follow in case practical results should 

 be attained. 



That a decrease in temperature would impede or retard the develop- 

 ment of ova has been known for a long time, and, without encumbering 

 this essay with references, it may be asserted as a truth based on phys- 

 ical reasons and facts. Physiologists and biological philosophers, such 

 as H. Milne-Edwards and Herbert Spencer, have recognized and dis- 

 cussed the influence of fluctuations of temperature on physiological 

 processes. Every genus, and perhaps even every species of fishes, in the 

 course of the early development of its ova, appears to present some 

 Idiosyncrasy of behavior w^hich demands that its characteristics shall 

 be studied before it is ventured to proceed with experiments of this 

 character. Practically the peculiarities of the ovum of the shad are 

 perhaps as well known as those of any species we are called upon to 

 deal with. 



Shad eggs after impregnation are relatively large, measuring from 

 one-eighth to one-seventh of an inch in diameter. When first extruded 

 Bull. U. S. F. C, 81 12 



