222 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.39. 



is steadily diminished until, by the time the female is sexually mature, 

 it is entirely gone and the tips of the maxillse are in contact with the 

 gill arch of the host. The female, therefore, is an inactive factor in 

 the union. The male was also fastened by an attachment filament 

 in the first copepodid stage, and his swimming legs degenerated 

 like those of the female. Hence he can not swim in his search for the 

 opposite sex. 



When the copepodid larvae attach themselves to their host several 

 fasten in immediate proximity. The author has repeatedly taken 

 two or three adults from the same spot on a gill arch, each female with 

 an attached male. Sometimes the attachment disks are actually 

 fastened together so that they have to be cut apart, and often the 

 discarded male filaments will be found close beside those of the female. 



It is scarcely possible that sexual instinct manifests itself thus 

 early in development, and induces the two sexes to attach them- 

 selves side by side. But there may well be a general instinct which 

 leads all the larvae indiscriminately to keep together during this 

 period. And this is exactly what the finding of several adult females 

 attached to the same spot would indicate. 



Having attached themselves as members of such a little group the 

 males, as soon as their sex organs are developed, begin moving around 

 in a circle whose radius is the length of the filament. Somewhere 

 within this space they are pretty sure to find a fenjale; the male then 

 fastens to her body with his maxillipeds and withdraws the claws of 

 the maxillae from the end of the filament, thus becoming perma- 

 nently fastened to the female. It is probable that, if the male can 

 not find a female by this method, he is able to withdraw his claws 

 from the filament and crawl about over the gill arch in search of one. 

 The discarded filaments found on the gill arches of the red-eye would 

 indicate at least that the male does not retain this attachment after 

 becoming sexually mature. 



GENERAL SUMMARY. 



1. Long filaments of ovarian cells loosen themselves from the 

 epithelium of the ovary and pass down into the uterine processes of 

 the oviduct, where the terminal cells of each filament develop into 

 oocytes successively, one after another. 



2. Each egg is surrounded by a structureless vitelline membrane, 

 within which are yolk globules evenly and universally distributed 

 thi-ough a fine cytoplasmic matrix. There are numerous scattered 

 spherical vacuoles of different sizes. The egg nucleus is about the 

 size of the largest vacuoles, is slightly eccentric, nearly spherical, 

 and surrounded by a membrane. It contains a single nucleolus and 

 numerous chromatin granules near the periphery. 



3. As the eggs pass out of the oviduct they are each fertilized at the 

 opening of the sperm receptacle, and are covered with a layer of the 



