INLAND FISHERIES. 07 



g-ood opportunities to obtain food, the starlisli becomes sexually 

 mature in less than one year, and that those hatched one season 

 breed the next. 



In his monograph on North American starfishes, Alexander 

 Agassiz gives his views M^th reference to the rate of growth of the 

 starfish in the following words : (The figures referred to represent 

 specimens, all of them smaller than that in our Fig. 9, of a star 

 about two weeks old raised in the car.) 



"The young starfishes figured ou this plate (PI. VIII) were all found attached 

 to roots of Laminaria, thrown up ou the beaches, in the neighborhood, after a 

 storm ; and from their different stages of growth, as compared with the oldest 

 starfish raised from a Brachiolaria (PL VI. Fig. 11) specimens of which were also 

 found upon these roots, it is probable that the sizes here figured are one (Fig. 1), 

 two (Fig. 8), and three (Fig. 10) years old. A considerable number of specimens 

 were picked up in this way, and they could all be arranged into very distinct 

 groups, representing the starfishes of the present and two previous seasons. 

 There seemed to be no gradation from one group to another, such as we have 

 among the young sea urchins, which, in consecj[uence of their manner of breeding 

 during the whole year, form series, the relations of which it is impossible to 

 determine. In this connection I would say, that by arranging the starfishes 

 found upon our rocks into series according to their size, we are able to obtain a 

 rough estimate of the number of years required by them to attain their full 

 development ; this I presume to be somewhere about fourteen years.* They 

 begin to spawn 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 starfish, 

 measuring one and a half inches across the arms, was kept, during five months, 

 alive in Mr. Glen's tank at the museum, and during that space of time it grew 

 to three inches." 



It will readily be seen that my oliservations do not at all agree 

 with those of Agassiz. I found no diificulty in obtaining all possible 

 gradations in size among the stars in the late summer, and the 

 stars represented by Agassiz as one, two, and three years old 

 respectively, more nearly correspond with those raised in cars 

 when they were one, two, and three weeks old. 



* For an account of the method adopted by Professor Agassiz for ascertaining the age of 

 many of our marine animals, see Proceed. Essex Inst., 1863, p. 252. 



