DIAPTOMUS. 225 



place, a body like one of these tubes may always be seen 

 concealed in the sexual parts ; but immediately after 

 copulation has taken place, nothing of the kind can be 

 observed in a state of development. Jurine, as I have 

 observed above, had occasionally seen them in the male, 

 attached to the base of the posterior feet ; and Siebold 

 states, that once, upon separating a pair in the act of 

 copulation, he found a seminal tube attached to the end 

 of the last pair of feet of the male, " apparently," he says, 

 "before he had had time to rid himself of the body." 



It has been observed, that the males of this species are 

 very lustful, and they have been seen to attack in succes- 

 sion several females, some of them even such as had had 

 connection immediately previous with other males, or that 

 had external ovaries suspended from their abdomen, so 

 that it is not uncommon to find two, three, four, and even 

 five of these tubes in the same female. These tubes are 

 all similar in size, form, and contents. They are straight, 

 and scarce extend in length beyond the point of the tail. 

 They are composed of a colourless, solid envelope, which 

 is rounded at its inferior free extremity, and terminates at 

 its upper end in a short, narrow neck, provided with an 

 opening. Each tube contains three different kinds of 

 matter : one is white and thick, of a glutinous nature, ex- 

 tending the whole length of the tube, and is coagulable in 

 water ; the second consists of a great number of very small, 

 oval, well-formed bodies, which Siebold considers the real 

 zoosperins of the animal ; while the third is composed of 

 a mass of oval bodies of a similar size, and composed of 

 very fine granules. This latter granular portion of matter 

 occupies the inferior half of the capsule ; the second portion 

 lies in the upper half, while the neck only is filled with the 

 first kind, or the glutinous substance. As soon as the 

 tube quits the sexual organ of the male, the relative situa- 

 tion of these substances changes. Immediately it comes 

 in contact with the water, the third or granular mass 

 swells, the little oval, granular bodies become round, swell 

 more and more, till at last they expel the first or .glutinous 



15 



