THE SPERMATOGENESIS OF THE SPIDER. 1/9 



been emptied from the cysts into the lumen. The process then 

 goes on very rapidly. Probably the degenerating cells of Pholcns, 

 if examined near the close of the breeding season would be found 

 to have lost their nuclei like those of Agalcna nccvia. It was 

 not found possible to make an accurate count of the two kinds 

 of cells in the ducts and hence it was not possible to determine 

 with certainty their relative numbers but it was estimated that 

 there were about three times as many of the degenerating cells 

 as of the normal, ripe spermatozoa. What could be the deter- 

 mining cause ? It will be remembered that there are three times 

 as many spermatozoa without the accessory chromosomes as 

 with them, and it occured to me that possibly only one fourth of 

 the spermatids, the " bevorzugten zellen," become functional 

 spermatozoa. Platner and O. Hertwig have shown that the 

 two divisions which form the polar bodies of the egg are homol- 

 ogous to the last two divisions of male germ cells but that while 

 in the female germ cell the products of division are very un- 

 equal in size and only one of the four is functional, in the male 

 germ cell they are equal in size and each of the four is func- 

 tional. If it can be proven that three fourths of the sperm cells 

 are aborted, just as three fourths of the ova are, the parallelism 

 in the spermatogenesis and ovogenesis will be found to be even 

 more complete than has hitherto been supposed. There are at 

 least a priori reasons for believing such to be the case and I was 

 still further strengthened in this position when my attention was 

 called to a short paper by Meves in which he describes the find- 

 ing of "polar bodies >: in the testis of the honey bee and other 

 Hymenoptera. " Die Spermatocyten I. Ordnung bei den gen- 

 annten Hymenopteren stoszen ebenso vvie sonst die Eier bezw. 

 Ovocyten I. Ordnung nach einander zwei "Richtungskorper" 

 aus ; von diesen besitzt jedoch nur der zweite einen Kern, wah- 

 rend der erste ausschlieszlich von Cytoplasma gebildet wird .... 

 Die ersten Richtungskorpen gehen nach einiger zeit zu Grunde. 

 Die zweiten Richtungskorper dagegen beginnen ebenfalls sich 

 zu Sprermien zu entwickeln, wobei ihre Kerne dieselben Veran- 

 derungen wie die Kerne der groszen zellen und zeitlich parallel 

 mit ihnen durmachen-jedoch scheint dieser Entwickelungsprozesz 

 schlieszlich, wenn auch erst sehr spat, zum Stillstand zu kom- 

 men und in Degeneration iiberzugehen." 



