NATURAL HISTORY OF THE STAR-FISH. 
221 
before that time, as specimens have been successfully fecundated which evidently were not more than 
six or seven years old. It is during the fourth year that the rate of growth seems to be most rapid. 
A young star-fish, measuring 14- inches across the arms, was kept during five months alive in Mr. 
Gleu’s tank at the museum, and during that space of time it grew to 3 inches. 
It will readily be seen that iny observations do not agree with those of Agassiz. 
I found no difficulty in obtaining all possible gradations in size among the stars in tbe 
late summer, and those represented by Agassiz as 1, 2, and 3 years old, respectively, 
more nearly correspond with those raised in cars when they were 1, 2, and 3 weeks old. 
XII. What are the natural enemies of the star-fish? 
The destructive agents and natural enemies referred to in the last report were 
cold and fresh water, various fishes which feed upon the larvse, gulls and crows, and 
parasites. Some specimens which were attacked by the parasite frequently found in 
the fall of 1897 were kept over winter, and by spring the disease had disappeared; 
but the effects of the disease were sometimes visible. In one case an arm was entirely 
eaten through, about % inch from the tip, but was not thrown off. The stump healed 
over, and the star was kept throughout the year. It showed almost no trace of 
regeneration, probably because food was rarely taken by the specimen. 
The enemy which is doubtless the most destructive to the star- fish is the men- 
haden. In an article on the “Food of the menhaden,” published in the United States 
Fish Commission Bulletin for 1893, Dr. James I. Peck showed that this fish feeds 
exclusively upon the minute organisms which swim or float free in the water. The 
open mouth of the menhaden has an area of about a square inch, and as the fish swims 
through the water with open mouth and gill covers raised, a considerable column of 
water is passed through the mouth every minute (estimated by Dr. Peck at about 7 
gallons). The gillrakers strain the water, and the organisms which are not too minute 
are caught in the mouth and swallowed. The star fish larvie, of even small sizes, are 
far too large to pass through the gillrakers. Numerous schools of menhaden feed in 
our bay during the season when the star-fish larvie are swimming at the surface, and 
undoubtedly destroy them by thousands of millions. 
After the stars are set they are no longer in danger of being destroyed by the 
menhaden, but for several weeks are bright conspicuous objects upon the seaweed 
and eelgrass for eels and many small fishes to feed upon. 
XIV. Is the popular idea that the dismembered fragments of a star-fish will regen- 
erate new star -fish founded on fact? 
This idea is commonly held, and is apparently founded on the fact that in nearly 
every lot of stars brought up in the dredges or on the mops a considerable number 
may be found which are regenerating lost parts. Frequently two, three, or even four 
arms are being regenerated, and these are much smaller than the original arms. 
Upon careful examination and inquiry into the extent of this regeneration I have 
never found a well-authenticated case among our species of stars in which part of the 
disk was being regenerated, except those reared with great care in the aquarium. 
With this point in view 1 have examined a large number of regenerating stars caught 
in their natural haunts, some of them reported to be regenerating part of the disk, but 
invariably the regeneration was limited to the arm. I have, however, made a few 
experiments in the aquarium and in the cars which have a bearing upon this question. 
The fact that a mutilated arm is frequently loosened and dropped off at a par- 
ticular point near the base and the rate of regeneration of specimens which have thus 
lost one or two arms are recorded previously (p. 219). 
