HABITS AND LIFE-HISTORY OF STICHOPUS JAl'ONICUS. 



7 



July. 



July 3, 1893 at Kanagawa. 

 3 large çf — Spawning finished, Reproductive tubes getting small. 

 6 large .^Beginning of the end of spawning. Reproductive tubes 

 3 large ) not as small as the above 3. 

 Spawning f past. 



July 31, 1894 at Kanagawa. 



Indivi, 

 duals 



Size of Individuals 

 LengthXBreadth 

 in cm. 



Condition of Reproductive Organs. 



I 



19.5 X 6 





Spawning finished. Reproductive tubes with d:rty pigment ; look exhausted 

 Anterior part of the alimentary canal empty. Posterior part still with sand 

 but not as large as formerly. Ready to retire under rocks. 



2 



18 X 5 





With some small spermatic tubes in ripe condition. 2nd year ? 



3 1 



18 X 5 





Spawning finished. Ovarian tubes grown very small with dirty 

 (probably) brown pigment. Alimentary canal with ve' y little sand. Ready 

 to retire under rocks. 



4 



24 X 3 5 





With some white spermatic tubes like No. 2 No sand in aliment- 

 ary canal. 2nd year ? 



In passing, I should like to add that it is impossible to separate 

 males from females by any external characteristics, all that fishermen 

 say to the contrary notwithstanding. 



These facts together with data from other localities which I need 

 not give may be summed up as follows : — After these holothurians 

 emerge from their summer hiding places and resume their activities, the 

 branches of the dendritic reproductive glands which are at first very 

 fine and slender, and only about 2 cm. long begin to elongate quickly. 

 I observed one year that by Dec. 6, the reproductive glands had the 

 maximum length of 10 cm., and I was barely able to recognize the sex. 

 By the end of January, they reach the maximum length of 16 cm., by 

 the end of February of 21 cm., by April 1 of 38 cm.; by the middle 

 of May the reproductive organs in many individuals reach the ripe 

 condition and is the beginning of the breeding season in earnest. Of 

 course there are many cases of ripe sexual organs before this, but they 

 must be considered as specially early ones. The largest individuals 

 seem to have their reproductive organs ripen before smaller ones. The 

 spawning season continues from the middle of May to the middle of 

 July which may be said to mark the beginning of the end. By the 



