No. 2.] THE DEVELOPMENT OF THE NEWT. 315 



place it ahead of all competition. Proximity and order of 

 entrance are undoubtedly the two factors that determine the 

 success of the sperm's quest. 



Polyspermy. — I have already meniioned that several sperm- 

 atozoa normally enter the ^%g of the newt. I may now state 

 that I have sectioned twenty eggs from two to ten hours old 

 and found in every ^gg superfluous male elements. The 

 number of these varied from one to thirteen and was in most 

 cases from six to eight. If it be objected (Born, Roux, 

 Hertwig) that such polyspermy indicates pathological con- 

 ditions, I may reply that these twenty eggs were all laid in 

 a normal way, by different females and at different times ; 

 that abnormalities are very rare in newt development and 

 that such a succession of non-developing or abnormally devel- 

 oping eggs would in my experience be unprecedented ; and 

 finally that I have in the living Qgv watched several sperm- 

 atozoa enter the upper pole and normal development succeed 

 in every case. There is thus every reason for regarding such 

 physiological polyspermy in the newt as a natural, normal, and, 

 in fact, usual occurrence. 



What now is the further history of these superfluous sperm- 

 atozoa which normally enter the Q.gg of the newt } In the first 

 place it is to be remarked that these accessory sperm nuclei 

 (Nebenspermakerne) undergo a progressive development after 

 their entrance. They increase in size, acquire a double- 

 contoured membrane, and show precisely the same affinity for 

 stains as the male element that fuses with the female pronucleus. 

 They are in all objective respects quite as competent aspirants 

 to union with the latter as is the male nucleus (Hauptsperm- 

 akern) actually honored. They owe their non-preferment not to 

 any intrinsic inferiority, but to the time and place at which 

 they entered the Qgg. These accessory sperm nuclei are most 

 numerous in the region of the upper pole, but are quite often 

 found stranded among the large yolk spheres of the lower 

 hemisphere. In the latter case they are usually near to the 

 periphery of the o^gg. 



The accessory sperm nuclei ultimately degenerate. Shortly 

 after the fusion of the two chief pronuclei the superfluous male 



