163 
or not, and by comparing the ratios of successive seasons, the 
increase or decrease constant or otherwise, could be ascer- 
tained, and the yield of the bed in ensuing seasons predicted. 
In order to . have another and more correct standard for 
comparison, and to arrive at certain conclusions as to whether 
the spatting in any season was general and extending to all 
beds or confined to particular localities, and in order to know 
accurately the number of oysters surviving each period of 
their perceptive existence, numbers of spat collectors were 
deposited upon the different beds. 
It was the intention to frequently inspect these tiles, and 
by counting the number of oysters on each tile at each ex- 
amination the number of oysters surviving would be ascer- 
tained, and the age of the previously established classes would 
be decided. 
Thus the life of a community of oysters, free from the 
dredging influence and protected from all but natural ene- 
mies, would be before us from the time of the first attachment 
until they reached maturity. 
The study of their embryological life properly belonged to 
the zoological student, and the method of propagation and 
the successive stages of that life must be left to him to deter- 
mine It is valuable to the inquiry under consideration, but 
not essential, as it is evident that we may neglect the early 
stages of life, and yet arrive at correct conclusions as to the 
number of mature oysters necessary to support the beds in 
their best condition. 
In next importance to the knowledge of the absolute fecund- 
ity of the bed, is a knowledge of those conditions which would 
influence it, and in order that no cause for the deterioration 
should be neglected, and that all information bearing in any 
way upon the propagation and growth of the oyster might be 
collected, several matters of secondary importance have been 
subjected to investigation and the results embodied in either 
this or my previous report. 
Included under this head are — 
Investigations into the temperatures and the influence of 
