508 P« E. Keucbenius, 



that where they are present, the tunica externa protuberates out- 

 wards very strongly (fig. lOw). In the externa I found sections 

 through tracheal tnmks. The interna (fig. 10 in) is developed in 

 the distal part of the testes, near the vas deferens (fig. 10 vd) as 

 a flat epithelium. Proximally it continues in a membraneous lining: 

 the membrana propria, in whieh nuclei are very seldom to be 

 discovered. In several places cellular septa (fig. 10 sept) go out from 

 the tunica interna and push into the lumen of the testes. In the 

 proximal part of the testes, I saw the younger stages of the ontogeny 

 of the germ-cells: gonocysts and cytocysts, whilst distally the 

 somewhat older stages: spermatocysts and ripe spermatozoa are 

 to be observed. It need not to be remarked that mitotical nucleus- 

 figuies are often to be observed. Besides these elements, I saw, 

 distally, numerous small globular, yolky bodies (fig. 10 y) of which 

 the origin and signification is hidden from me. They may possible 

 be rudiments of nuclei, derived from degenerated cysts. A closer 

 investigation of the development of the testes and their contents 

 may probably find out the origin of those yolky elements. Of an 

 apical-cell, there is no trace whatever. 



The two vasa deferentia (fig. 9vd) are only very short. They 

 run straight to the median, where they join. Their coverings are a 

 continuation of the Investments of the testes, while the tunica ex- 

 terna, too, keeps its pigmented character. The junction of both 

 vasa deferentia to an unpaired vas deferens, is but apparent 

 as we shall see. A section of the unpaired vas deferens is drawn 

 in fig. 12, where we observe that both the epithelium tubes continue 

 independently in the unpaired vas deferens, the tunica externa 

 of which, however, has become common for both. The unpaired vas 

 deferens runs along caudally without making any windings and 

 then bends with the abdomen on the right side (fig. 9 u.vd) in a cranial 

 direction. 



The two accessorial tubes (fig. 9 acc) run about parallel with 

 the unpaired vas deferens; at their beginning they are situated 

 in the left side of the abdomen and of the unpaired vas deferens 

 (fig. 9). The externa of them is exceedingly thin and contains small 

 flat nuclei (fig. 11 ex). The tunica interna lining the accessorial 

 gl and s is a rather flat epitheUum with round nuclei, which does not 

 immediately give the impression of a gland-epithelium (fig. 11). The 

 lumen. of the accessorial gland-tubes, consisting of the secreta 

 and getting only slightly coloured, and the seamed edge formed by 



