20 ART. H. — A. 1ZUKA : OBSERVATION ON THE 



somewhat vertically, and by a sweeping motion the worms, as 

 they come along with the ebbing tide, can be scooped up with 

 convenience. 



The swimming worms are attracted in numbers by the light 

 of a lantern, which greatly facilitates the collecting. In the 

 aquarium, a candle-light readily attracts them. Whereas, in 

 the case of non-swimming atocons worms I have found that the 

 same light exercised no such influence. 



The epitocœ, after being captured, can be kept alive for a 

 week or two in shallow wooden vessels placed in a shaded place 

 and with a small quantity of the river-water taken at the time 

 of high tide, just enough to cover the worms. The water must 

 be changed once or twice a day, taking care to remove all the 

 rent or otherwise injured worms as soon as possible, without 

 which precaution the water will soon become so filled with dis- 

 charged sexual products as to be detrimental to the general 

 health. Too much water, as also much light, induces the worms 

 to motion and thus increases the chance of receiving injuries to 

 their body. 



As might be expected, the worms are apt to fall prey to 

 iishes while swarming. On one occasion I chanced to capture 

 two Leuciscus hakuensis, which were evidently in pursuit of the 

 swimming worms. On dissection, they were found to contain the 

 worms in the stomach or sticking in the throat. 



Size. — The dimensions of the epitoca vary considerably in 

 different individuals, as the direct result of the fact, already 

 mentioned, that differently sized atocas undergo the change into 

 epitocae. 



I have found males measuring between 40 mm. and 130 mm. 



