MELANENCHYTRAEUS SOLIFUGUS 



appears. As a whole, these clusters have the aspect of glands, but no 

 excretory duct could be detected. The aspect of the white and strong 

 refracting granules leads me to think that they are uric products, and that 

 the function of these problematic organs is excretory. 



The dorsal vessel, or heart, appears on the sections from the 12th segment 

 towards the head. Its posterior end is therefore neither praeclitellic nor 

 postclitellic, but intraclitellic. This includes a cardiac body, or cardiac 

 gland, of irregular shape, made of a small number of cells, in each transverse 

 section. Having at my disposal only preserved specimens, I could not 

 observe the colour of the blood ; I was unsuccessful in reconstructing from 

 the sections the distribution and course of the blood-vessels. 



The lymph cells seem to be all of one sort ; I have drawn some in Fig. 14. 



The nephridia (Fig. 15) are of irregular shape, with few large nuclei; 

 the cells corresponding to these nuclei are not clearly outlined. Nearly 

 the whole mass of the nephridium is built by the intricate and densely 

 coiled tube. The wall of the excretory duct is thick and pigmented 

 as it approaches the external opening. The latter lies on the line of 

 the ventral bundles of chaetae, in front of the bundle of the segment in 

 which it opens. 



The testicles and ovaries offer no noteworthy peculiarities ; in my speci- 

 mens the latter were little developed, even in the most mature, in which the 

 spermatogenesis was rather advanced. This fact indicates a condition of 

 proterandry. 



In the more developed specimens enormous sperm-sacs extend from the 

 lOth to the 15th segment, and fill nearly the whole body-cavity. We find 

 in them all the stages of spermatogenesis — large spermatogonia, sphseric 

 follicles derived from multiplication of them, and bundles of very minute 

 zoosperms ; the latter are, however, in small numbers. But in most of the 

 specimens I did not observe sperm- sacs nor spermathecae ; testicles and 

 ovaries were very small and the sperm-ducts wanting, their distal part only 

 being recognisable as a rudiment. 



My Fig. 16 gives the reconstruction of the left sperm-duct from a series 

 of sagittal sections. The funnel {in) opens in the cavity of the nth 

 segment. It gives rise to a somewhat twisting tube, which runs backwards 

 as far as the 15th segment, where it is tightly coiled ; from there it returns 

 forward to its external opening in the 12th segment. The last tract forms 

 a spherical bulb («), but before reaching it the tube presents a fusiform 

 swelling {c), whose wall is very thick and made of long cells, directed 

 radially on the transverse section, the lumen being not widened. Bundles 

 of prostatic (spermiducal) glands {b) are related to the bulb ; another little 

 group of glands {e) lies around the tube, above its fusiform thickening. As 

 I mentioned above, the 12th segment, in which the sperm-duct opens, is 

 deficient in ventral bundles of chaetae. 



I have given in Fig. 17 a reconstruction of the spermathecae, made from 

 a series of transverse sections of the most developed specimen, which I 



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