No. 397.] FOOD SUPPLY IN STARFISH. 23 
setting, and their sex glands were quite as well developed as 
they were in the average stars of any size at that season of the 
year. Allowing the very moderate estimate of 15 mm. for the 
growth of such individuals during the next six months, in May 
they would be more than 50 mm. in length, and such speci- 
mens are, with rare exceptions, sexually mature. We are 
warranted in inferring, therefore, that well-nourished star- 
fishes arrive at sexual maturity and breed before they are a 
year old. 
On the other hand, it is evident that many starfishes do not 
reach sexual maturity in one year, since small, immature speci- 
mens, between 10 and 20 mm. in length, are not uncommon 
just before the breeding season begins. 
Desultory observations on other marine invertebrates, e.g., 
the clam, oyster, and lobster, indicate that the conditions of 
their growth are essentially similar to those of the starfish, and 
to this extent substantiate the conclusion that between the 
higher and lower animals there are fundamental differences in 
the phenomena of growth. 
BROWN UNIVERSITY, 
November 9, 1899. 
