34 REPORT OF COMMISSIONERS OF INLAND FISHERIES. 
that in one month they became about three times the bulk of the 
latter. There is one possible fact, however, which may make this 
result less trustworthy than the data derived from the growth of 
marked individuals or from that of the largest specimens in each 
locality, viz.: the clams which were placed in the house-boat were 
gathered with a sieve, which, though its meshes were small (ordi- 
nary flour-sieve), may have allowed many of the smaller clams to 
go through; so that the average size of those planted was perhaps 
less than the average size of those remaining on the shore. 
The actual increase in bulk of a certain quantity of clams dur- 
ing ten weeks in the summer is given in the following measure- 
ment of the clams reared in the house-boat. The box of sand 
in which a pint and a half of small clams was planted as evenly 
as possible, on July 6-9, was divided in the middle by a par- 
tition. The clams soon became so crowded that many were 
probably pushed out; at any rate there was a considerable num- 
ber of empty shells over the surface of the sand. Notwithstand- 
ing this loss, four and a half quarts were taken from one-half of 
the box on September 18, the other half being left undisturbed. 
From about three-fourths of a pint, therefore, we had a yield of 
over four quarts of clams in about ten weeks. We ought also to 
mention that one pint was taken from the box on August 5, and 
smaller quantities on several other occasions. 
Size and Age at Sexual Maturity. 
It is usually maintained that the clam reaches sexual maturity 
during the third year of its life,* but I am inclined to believe that 
this does not do justice to the animal in question, and that the 
clam, like the star-fish, not only grows faster, but arrives at sexual 
maturity much sooner than is usually supposed. My reasons are 
as follows :— 
1. I found at the beginning of the breeding-season a ripe male 

*See Bulletin 51, R. I. College of Agriculture and Mechanic Arts, December, 1898. 
