1 1 AB ITS AND LIFE-HISTORY OF STICHOPUS JAPONICUS. 



'3 



why they become attached to little sheltered recesses or crevices in the 

 roots of algai, gorgonians and other similar organisms. 



A reference to what has been said in the earlier part of this paper 

 shows that spawning is still going on in the latter part of July. We 

 must therefore suppose that these young individuals have come from 

 the eggs which were shed early in the season. This seems to put a 

 limit to the duration of the free larval life which can not exceed at the 

 most three or four months — being in actuality probably much shorter. 



At Kanagawa where there is no rocky ledge that was exposed and 

 could be examined minutely at low tide as at Koajiro (Misaki), it was 

 not possible to detect any specimens as young as those above-mention- 

 ed, but here I carried on more or less through three years (1893-5) a 

 series of observations casting light on the growth of young individuals. 

 For some time I was considerably puzzled over the age of individuals 

 dredged up at any one time, although it was evident that there were 

 great differences in this respect. On Dec. 2, 1893, I, however, succeed- 

 ed in dredging three specimens which gave me a starting point. Their 

 lengths and breadths were respectively 4.8 cm. X 9.0 cm., 3.9 cm. x 1.2 

 cm., and 6.0 cm.y. 1.5 cm. Their skin was very thin, very pliable, still 

 half-transparent allowing the viscera within to be seen through, and 

 somewhat greenish in color. They were so distinctly younger and 

 could be so readily distinguished from older ones that there could be no 

 doubt as to their being of that year's brood. These I called the first 

 year individuals. 



From this time on, the study of growth was comparatively easy. 

 As mentioned before, my observations extended over three years or 

 more, but the series from October, 1894 to June 1895 is the most com- 

 plete and will be given first in the following table. On Oct. 17, 1894, 

 two first-year individuals (1.2 cm. X 0.6 c m. and 2.4 cm.X. 1.2 cm.) were 

 obtained for the first time that autumn. On the next day, 18 

 specimens were dredged. These are the first catch recorded in the 

 table. 



