THE SPERMATOGENESIS OF AGALENA N/EVIA. 14! 



for the sperm-cells until they reach the ova at the time of ferti- 

 lization. 



In my first study of PJiolcus plialangiodcs, already referred to, 

 it will be remembered that two kinds of degenerating cells were 

 found in the lumen of the testis, half containing nuclei and half 

 not. I have now found that these bear no genetic relation to 

 each other but arise in totally different ways. Those without 

 nuclei are the cytoplasmic remains discarded by the spermatozoa 

 and which accompany the latter when they pass into the lumen of 

 the testis. Those containing distinct nuclei originate from degen- 

 erating spermatids, many cases occurring where nearly all or quite 

 all of the spermatids in a cyst are in advanced stages of degenera- 

 tion. The cell-body becomes enlarged and vacuolated and the 

 chromatin forms homogeneous-looking masses irregular in out- 

 line or fragmented (Fig. 60). These cells greatly decrease in 

 circumference, the chromatin mass becomes spherical, and the 

 cell body becomes so transparent that it is easy to overlook it 

 altogether. They vary considerably in size, even after they have 

 passed into the lumen of the testis but they are readily distin- 

 guished from the ripe spermatozoa and the granular cytoplasmic 

 bodies among which they lie (Fig. 61). 



In Agalena, although in the breeding season the sperm ducts 

 are fairly packed with nearly colorless cells or fragments of cells 

 in which the ripe spermatozoa lie embedded, none of the former 

 appear to contain chromatin, or, if they do, it is so finely dis- 

 tributed that it stains very faintly. Neither in this spider have I 

 found cysts full of degenerating spermatids. After a careful study 

 of the cysts containing nearly mature or mature spermatozoa, I 

 am thoroughly convinced that Bosenberg is correct in stating 

 that the ripe sperm-cells wriggle out of the cell body and further- 

 more he claims to have actually witnessed the process in his ex- 

 amination of living cells. I have, in fixed material, found the 

 sperm-cells in all stages of the process and the phenomenon is of 

 too common and too general occurrence to be accounted for by 

 the tearing action of the microtome-knife in sectioning. After 

 the spermatozoa have wriggled themselves free, they remain in 

 the cyst for some time before the rupture of its walls and during 

 this time, while they are contracting and rolling up into a 



