118 BULLETIN OF THE UNITED STATES FISH COMMISSION. 
so well liow to avoid the attack. On the other hand, I never saw a 
crab larva attacking the cod, so they may grow and develop peace- 
ably together, for a time at least. That the larvae at last succumb to 
the voracious cod is certain, but not until his size is considerably larger 
than the crab. As the cod, when larger, very seldom attack and eat 
each other, we may conclude that the greediness which they at present 
have is because the basin is new, and only a few sea-plants are yet 
growing there, so that there is not sufficient food in it for such a number 
of fish. Tried to feed them and succeeded in getting some of them to 
swallow pieces of finely-powdered mackerel. 
June 19. — During the course of the last nine days numbers of cod have 
been examined, and their stomachs were filled with several kinds of 
animalcule, such as mosquito larvae and pupas, of which there is an 
incredible number in the basin. There were also found in them part of 
the food daily thrown into the basin for them. Some were found dead 
by the overflow, and marks of outside violence were visible, their hind- 
parts bloodshot and the skin injured. 
When the young cod leave the egg they have a length of 3 millime- 
ters. During the first eight days, while the yolk sac is able to give 
sufficient nourishment, they grow 2 millimeters, so that when taken out 
of the apparatus they have a length of 5 millimeters. [It takes a trifle 
over 25 millimeters to make 1 inch, so 5 millimeters equal about | inch.] 
Their future growth is varying indeed, and depends more perhaps on 
the difference in race kinds than on the greater or less quantity of food 
they succeed in obtaining ; and when in the following table I give their 
length, it must be understood to be the average : 
Date. 
Age. 
Length in 
millimeters. 
Length in 
inches. 
A pril 26 
Days. 
0 
3 
.12 
May 3 . 
6 
5 
.20 
May 16 _ 
19 
7 
.28 
May 18... 
21 
8 
.31 
May 21 - 
24 
9 
.35 
May 31 
35 
10 
.39 
June 3 
38 
12 
.47 
June 6 
41 
15 
.59 
July 12 | 
77 
55 
2. 17 
August 12 
108 
70 
2. 76 
September 12. ... 
139 
85 
3. 35 
4. 53 
October 12 
169 
*115 
* The largest one caught at this time was 157 millimeters [or 6.18 inches! long. 
Between the 6th of June and the 12 th of July there is a very large 
step in the development, as the table shows; but the reason is that at 
this time the young cod begin to eat the food given them twice a day, 
and in considerable quantities. 
From the middle of October until now (middle of February) their 
growth has been very slow, the causes of which may be easily ex- 
. - - ' 7 : 
