190 
The second examination was on August 2d, and the oysters 
were then quite perceptible and easily counted. 
The total number of oysters on the tiles was then 1,506 ; 
deducting those on tile No. 7, there were 1,177. 
The number on each tile varied greatly, the maximum being 
348 and the minimum 26. 
The third examination was on the 23d of August. The 
oysters had increased very much in size and in numbers. The 
total number on the tiles was now 1,334, showing an increase 
of 0.13 per cent, of the number at the second examination. 
The number on the lower side of the tiles was much larger 
than on the upper. 
A tile (No. 2) was removed, and, deducting the number of 
oysters on it from the sum, there were 1202 still on the hur- 
dle. 
There were a few oysters injured, probably, by raising or 
lowering the hurdle from and to the bottom. 
The fourth examination was on the 10th of October. 
The total number of oysters was then 539, showing a de- 
crease of 55 per cent. 
At this examination about two- thirds of the oysters were of 
the third class, or over three-quarters of an inch in length, 
and two of them were over two inches long, being thus of the 
second class. All, however, could be distinguished as of very 
recent growth, being very long and thin, with thin, delicate 
shells, easily broken with the thumb-nail or point of a pen- 
knife. 
The largest numbers were still found on the lower sides of 
the tiles. 
A moderate number of oysters had been injured by rough 
handling. 
1 infer from the four inspections made of this hurdle, and 
from the one or two made of others before they were removed, 
that the first attachment of young began, as I have said, 
about the middle of July, and continued until about the twen- 
tieth of August, as on the 23d of that month there was no 
indication of any recent attachment. Probably it reaches its 
