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extremity, undoubtedly represents the alimentary cavity. Dorsally, at each side 

 of the latter, a narrow bandlike body tirst makes its appearance, extending 

 through the greater part of the body, and having its anterior extremity slightly 

 dilated (see fig. 9 5 )- These bodies are converted in to the ovaries, which in a later 

 stage (fig. 6 ), constitute 2 rather large lobular organs filled with numerous very 

 small ovicells. In the lateral walls of the body several short muscles are seen 

 passing from one segment to the next in succession, indicating that the body in 

 these stages is capable of some slow vermiform movements. All these inner 

 parts, however, at last wholly disappear, and the body of the fully-grown female is 

 converted merely into an inert capsule filled with ova or embryos. It often hap- 

 pens that several young females are found attached to the same Cypridina; but 

 of these only one becomes fully grown and ovigerous, and it is very probable 

 that the others soon die off without reaching full maturity. The position of this 

 parasite in relation to the body of its host is quite contrary to that advanced 

 by MM. Giard and Bonnier as an unexceptional rule for all Epicarida, the fore- 

 part of the body always turning the same way as that of the host. 



The male is found creeping freely on the body of the Cypridina or on 

 that of the female (see fig. 9 6 )- It is undistinguishable from the female in the 

 last larval stage, except by the nature of the generative organs, and it is even 

 not improbable that, after its function has been accomplished, it becomes con- 

 verted into a female, and that this form accordingly is protandric in character, 

 as has been suggested for some other Epicarida. 



Occurrence. I have not infrequently found this interesting form off 1 the 

 Lofoten Islands and at Bodo and Selsovig, infesting Cypridina norvegiea Baird, 

 an Ostracod occurring in great abundance on a muddy bottom in depths varying 

 from 100 to 300 fathoms. The parasite, when fully developed, is easily obser- 

 vable through the semipellucid valves of the Cypridina, always occupying the place, 

 where otherwise the ova and embryos of the latter are carried during their deve- 

 lopment. Occasionally the parasite also occurs on male Cypridinse ; but in no 

 instance have I found it in this case fully developed, and it is very probable that 

 under such circumstances it does not ever reach maturity. Out of Norway this 

 form has not yet been recorded. 



