12 Mindeskrift for J. Steenstrup. XVI. 



The inner organisation of the male (Fig. 4) is much the same as that of the 

 female. Regarding the genital organs we find two ovoid testes (te) in the head, 

 connected, as is the case with the ovary, by means of a narrow trans verse bridge. 

 The spermaduct (vd) corresponds in shape and course to the oviduct; near the testis 

 it is a little narrowed but widens soon, keeping the same width to the third thoracic 

 segment; here it suddenly narrows for again to expand into a sausage-shaped terminal 

 part, opening with a pore into a space corresponding to the female vagina, lined with 

 cuticle and covered by the genital opercle. 



The peripheral part of the testis contains genital cells, the central part spermatozoa. 

 The epithelium of the spermaduct is made up of columnar cells with large nuclei, 

 leaving a narrow lumen; in the terminal part the cavity is wider. In each duet a 

 spermatophore is formed, consisting of a long thread-like neck, reaching from the 

 testis till past the constriction, and a sausage-shaped expansion or "receiver", almost 

 filling the terminal part. Thus, during copulation, two spermatophores are discharged 

 at the same time; as already mentioned they may be found adhering to the genital 

 slits of the female. 



The stomach (in) seems more elliptical, the front end as well as the posterior 

 being narrower than in the female; otherwise the alimentary canal agrees in both 

 sexes, also as regards the presence of a "stone". The nervous and the muscular 

 systems are also alike; only the muscles are stronger and therefore more easily seen. 

 In the abdomen, however, the median transverse muscles differ considerably: they 

 are fanshaped, originating widely spread dorsally but inserted as in the female at 

 the junction of the ventral longitudinal muscles. The paired nature is clearly shown 

 only by the proximal bundle, and only at their origin. 



The stronger development of the muscular system in the male and the more 

 strongly marked segmentation of its body suggest a greater agility than in the case 

 of the female; probably it has to leave its own capsule and work its way into that 

 of the female, with which it wants to copulate and afterwards to stay. 



How far the living Chordeuma obesum possesses any colour, I am unable to tell, 

 as I have only seen specimens preserved for years in spirit. At all events no dark 

 pigment is found, and the preserved specimens are colourless. As the eggs some- 

 times show traces of pink colour, I think they may be more intensely red in the 

 fresh State and may give a certain amount of colour to the transparent body of the 

 female. 



II. The development. 



The eggs of the egg-mass contained in the gall are spherical and provided with 

 a thin shell. Before cleavage their diameter is 0,160 — 0,184 mm, when containing an 



