3o8 JORDAN. [Vol. \- II I. 



upper part of the oviduct exhibit the disposition of chromo- 

 somes seen in Figs. iS and 21. This must be taken as indi- 

 cating the metakinetic separation of the chromosomes, and 

 apparently foreshadows the speedy formation of a polar body. 

 This view is strengthened by the fact that eggs in the lower 

 part of the oviduct are all in the quiescent " equatorial plate " 

 stage as shown in Fig. 19. In this condition they remain until 

 after the egg is deposited and spermatozoa have entered. 

 About one hour and a half to two hours after deposition the 

 second polar body is expelled (Fig. 20). The minute size of 

 this body in the newt, as indicated in Fig. 20, is j^robably the 

 reason for my failure to discover it after expulsion. 



The esfss of the newt often remain in the oviducts un- 

 changed for at least forty-eight hours. I have elsewhere stated 

 that newts freshly captured from the ponds during the months 

 of May and June are almost invariably found to have eggs in the 

 oviducts. These individuals when brought to the laboratory 

 and placed in aquaria do not as a rule deposit their eggs until 

 the second day after the capture ; the eggs thus tardily de- 

 posited develop normally. The number of eggs that is usually 

 laid in the course of twenty-four hours (see p. 276) seems to 

 indicate that at least twenty-four hours is required for the 

 passage of an q.%^ down the oviduct. Not more than ten or 

 twelve eggs are found in an oviduct at one time, even in a 

 large female. The formation of the protecting membrane takes 

 place along the whole length of the oviduct, but is most 

 active in the middle and lower thirds. 



Note. — Since finishing this paper I have received Bern's paper upon 

 the maturation of the amphibian ovum (Die Reifung des Amphibieneies und 

 die Befruchtung unreifer Eier bei Triton tasniatus, Anat. Anz., VII., 1892, 

 p. 772). Bern's account of the continuity of the chromatin filaments fully 

 corroborates what I have found in Diemyctyhis^ and renders completely un- 

 tenable the view that the "skein" in the older eggs is constructed out of 

 fragments of disintegrated nucleoli. 



The only mention of a yolk-nucleus is on p. 777. Until Born certainly 

 identifies this " finely granular, oval body " with the yolk-nucleus of other 

 authors it would be unfair to criticise his singular statement that " in diesen 

 Gebilden das Archoplasma und die Centrosomen des Keimblaschens zu 

 suchen sind." 



