CANTHOCAMPTUS. 207 



has both stalks divided into three articulations, the ex- 

 ternal having all three of nearly an equal length, whilst 

 the internal has the first articulation nearly as long as all 

 the three of the external put together, but the last two 

 short, and inclined outwards. The three succeeding pairs 

 (f. 5 g, h) have the internal stalk shorter than the external, 

 both consisting of three joints, though Jmine says the 

 external has five. The fourth pair are the longest of all. 

 The fifth pair (f. 5 i) are small, and rudimentary. They 

 are situated under the fifth segment, and consist each of 

 a flat body, from each side of which issues an appendage 

 furnished with several hairs, the external being the longer, 

 and giving off a number of setse also from its external edge. 

 In the male they have been considered as the organs of 

 generation. 



At the base of the sixth ring in the female are the 

 openings of the canalis deferens, and under the sixth and 

 seventh segments the adults of the same sex carry a very 

 singular, horny-looking, club-shaped organ, wdiich is 

 fastened to the body by a narrow, elongated stalk. It is 

 somewhat curved, and directed backwards ; its colom* 

 being almost always more or less of a red hue. This organ 

 is not found in the young female, nor till after she has 

 several times laid eggs. Its hardness is greater than that 

 of the shell or carapace of the animal. Jurine has seen 

 two in one female, one red, the other black. Its use is 

 unknown. 



M. Siebold has conjectured its use to be the same as 

 that of the elongated tubes occasionally seen in the females 

 of Diaptomus (see the description of that genus) ; and 

 asserts that he has seen these bodies suspended over the 

 genital region of the female, and still inclosed in the 

 deferent canals of certain males, which by their antennae 

 were attached to the tail of the female. He never saw 

 the male, however, fasten this body to the female. 



Jurine says that this body is never seen in the female 

 till after she has several times laid eggs , In my own ex- 

 perience, I have never seen more than one body attached 



