Znv Kcnntniss der Speniiato^ü'oncsc von (Ti\yHotaIi).'i vul^'aris Latr. 125 



G) Dllring- tlie forniation of the second polar bod}^ the 

 sperniatic cell enters into the cg'g-cell. The nncleus of the spcrni 

 cell is, as a general tliing, at tirst rather sniall and colours deeply 

 and JHtniog-eneoiisly, bnt soon the differeutiation sets in and the 

 t'oiir chroniosonies beconie distinctly visible. The nncleus of the 

 cg'g"-ccll remaining- after the forniation of the second polar body 

 — thcfemale proniieleus of Ed. van Beucden — shows at lirst di- 

 stinctly four Clements. These soon grow longer, sliow niany con- 

 voliitions, and pass into a „skein" stag-e. 



7) The two niiclci gradually approach one another until 

 tliey conie in close contact, biit tliey do not unite into a sing-le 

 piece before the eqnatorial plate is fonued, The nund)er of chro- 

 niatic elenients in eacli of the copulating- nuclei is now found to 

 be eig-htj exactly double the nundjer present in the luaternal nn- 

 cleus after the expulsion of the second polar body, and in the 

 ripe Spermatozoon. 



This niind)er g'oes nncbang-ed to the forniation of the tirst 

 seg-mcntation s})indlc, which gives rise to two tirst segmentation 

 s})heres, each of which contains eight single chroniosonies." 



Aus den theoretischen Betrachtung-en Ishikawas will ich 

 noch folgenden Passus citiren: 



„Henking- tries also to niake his observations coincide will 

 those of Hertwig" upon Ascaris by giving- different interpretations 

 to the results obtained by the latter investigat(»r. Whatewer may 

 be the Interpretation in the case of Ascaris, my own case, g-iven 

 above, can not to my miiid be made to coincide with his Obser- 

 vation on Pyrrhocoris. 1 will not, however, assert the „Reductions- 

 theilung" in the forniation of the second polar body and in the 

 last cell division in the spermatogenesis to be the universal rule until 

 a sufficient number of ol)servations be obtained in otlier g-roups 

 of animals and perluips of plaiits too. Theoretical considerations 

 concerning the pheiioiiiena of fertili/ation lead us in all })robabi- 

 lity to the „Reductionstheilung-" as oceuring- in the second polar 

 body and in the last division of sperniatic cells," 



Verg'leichen wir jetzt einmal der Reihe nach die Befunde 

 der eben genannten Autoren mit meinen Resultaten, so werden 

 wir sehn, dass einer einheitlichen Auffassung der Reductionsvor- 

 g'äng-e nichts im Wege steht, wenn mau nur eine g-ering-e Aende- 

 ruuü' in der Deutuu"- dieser Befunde vornimmt. Mit den Ilert- 



