Hector F. E. Jungersen: Chordeuma obesum, a new Parasitic Copepod. 7 



In the living or fresh animals probably a great deal of the inner s true ture 

 may be observed directly through the transparent cuticle. In adult females preserved 

 in spirit only part of the genital organs is distinctly seen as a broad stripe of densely 

 packed eggs on each side, reaching almost from the front end of the head to the 

 posterior limit of the third thoracic segment; generally more than the middle third 

 part of the whole breadth of this region of the body is taken up by the egg-stripe. 

 The foremost roundcd end of the latter contains the ovary, the rest is part of the 

 oviduct, distended by eggs, still unfertilized and without membrane. Specimens stained 

 and cleared in glycerine, or better in xylol, reveal considerably more of inner structures. 

 Especially if young, unripe females are used, a fairly complete view of the inner 

 organisation may be obtained. For sake of controI and for further examination 

 microtome-sections, after imbedding with parafm, have been made. The cuticle, 

 thick and leathery as it seems to be, is no real obstacle; the tissues are casily stained, 

 imbibition with parafm and the cutting into sections are performed without difficulty; 

 in many cases complete series of very thin sections have been obtained. In the same 

 way males and larval stages have been studied. 



Genital organs. (PI. I, Figs. 8, 9). There are two ovaries (ov), situated in 

 the head. Each is a lenticular body sending out from its media) margin a short and 

 narrow transverse branch to connect with the corresponding branch from the opposite 

 side, thus forming a bridge dorsally across the stomach (if the branches really are 

 completely fused at their meeting point or a dividing membrane is left here, I have 

 not made out with certainty). The anterior and medial margins with the bridge 

 contain small genital ceils; the remaining part of the ovary is taken up by consider- 

 ably larger egg-cells. From the lateral and posterior part passes out the oviduct (od), 

 the greater part of which runs straight to the third thoracic segment and is laterally 

 }<omewhat compressed; distended with eggs, as in ripe females, its transverse section 

 is ovoid; when empty, as in unripe females, the shapc is moro rounded. The epithelium 

 of this part is almost cubic. In the ripe females the eggs contained in the oviduct 

 increase in size from before backwards; near the ovary they are only somewhat larger 

 than those of the ovary; from here and through the head they may be arranged in 

 two strata, in the thorax according to their size they are arranged in a sinf^e 

 stratum, but in several rows and so densely crammed that their shape is moro or 

 less angular. In the third thoracic segment the oviduct suddeniy nnrrows for im- 

 inediately again to expand into a sausage-shaped lernunal part, the epithelium of 

 which is high and secreting. In the interiør of this part I never found any eggs but 

 more or less of a secrction, staining deeply with hæmatoxyline, carmine (hæmaiuiii) 

 etc; the piling up of eggs always ceases at the con.striction. Probably the eggs on 

 bcing laid pass rapidly through the terminal part, the epithelium of the latter yielding 



