514 P- E. Keuchenius, 



base of the gland-cells gets rather intensively stained, but the remain- 

 ino- part only very weakly, in consequence of which the cell-limits are 

 very difficult to observe. The gland-cells of two foldings situated 

 side by side, nearly touch each other, so that the radial fissures are 

 exceedingly delicate. The meaning of the glandulär part of the vasa 

 deferentia is undoubtedly the secretion of the liquids for thinning 

 and liquifying the sperm. The function of the missing accessorial 

 glands is thus taken over by a part of the vasa deferentia. 



Both vasa deferentia join caudally forming the ductus eja- 

 culatorius {iig. 21 d.ej). The tunica interna of the ductus eja- 

 culatorius is composed of an epithelium whose altitude varies, in 

 consequence of which the lumen shows very irregularly (fig. 25 in). 

 The tunica externa is a rather thick layer in which, besides a great 

 many flat nuclei, there is also to be observed a fragile striping in trans- 

 versal sections (fig. 25 ex). Without doubt the externa is here com- 

 posed of more layers of ring- muscle-f ihres. The ductus ejaculato- 

 rius, as fig. 20 shows, makes a single bend and opens into the sac- 

 culus ejaculatorius; near its end it has become a little narrower. 

 The ductus copulatorius forms here, too, the connection with the 

 outside. The sacculus is provided with an apothetes ejaculato- 

 rius and its structure is like that of the already described specimens. 

 The same Observation applies to the structure of the ductus copu- 

 latorius. 



Farn. Muscidae. 



Dexia canina Fab. (Fig. 26 — 29). 



With the male genitalia of Dexia canina the accessorial glands 

 are missing, so that they are only composed of the following parts: 

 two testes with their vasa deferentia, ductus ejaculatorius 

 and sacculus ejaculatorius (fig. 26). 



The testes (fig, 26 t) are two oval bodies, which are pointed a 

 little at their apex. They are placed ventro-laterally of the gut, the 

 left testis more caudally than the right. Occasionally the left testis 

 is to be found a little dorso-laterally of the gut. The testes are not 

 surrounded by the fat-body. Two cell-layers form the Investments 

 of the testes. The tunica externa (fig. 27 ex) is a brown pigmented 

 layer with only a few nuclei (fig. 27 n) and in which tracheal trunks 

 are ramified. The tunica externa easily tears off from the tunica 

 interna (m). The tunica interna appears quite distally, near the 

 contmuation into the vas deferens, as a cellular epithelium, which 



