SYN APSIS 381 



often jumbled, sometimes extended along the length of the two 

 uteri. 



Fertilization is preceded by increase in size of that cell of the 

 speraiatidian tissue adjacent to the ovum next to be fertilized and 

 its transformation into a cell, spermule, having the form, and dis- 

 charging the functions, of a nemic sperm as hitherto understood; 

 a transformation involving a growth of about 50 per cent in diameter 

 together with a greater growth longitudinally, and & marked change 

 in the granulation of the cytoplasm (spml, Fig. 12). These trans- 

 formed cells, detached one by one, fertilize the eggs in what seems a 

 normal manner. The polocytes seem normal. The female gamete 

 has seven chromosomes (Fig. 13). 



The spermatidian tissues -tissues J 1 



, 



whose history seems to justify US in parasitifera, in synap- 

 j . , i i sis. Above, cf zygote. 



regarding them as spermatophores, Below, 9 nucleus in 

 may be removed from either the male synapsis; one set of 



chromosomes shown 



or the female nema and then separately behind the other and 

 stained and examined, and this has 



been repeatedly done; hi which case scured by their posi-; 



the details of their structure can of 



course be seen with greater ease and || 



distinctness than is the case with such |; 



living preparations as are shown in |;| 



figures 1 and 12. The enumeration %| 



of the elements of the 128-cell stage ; < V 



of the spermatidian tissue was found ^~~^<^_^~~~^^ 



possible in this way, as well as in balsam specimens fixed in corro- 



sive sublimate and stained in Mayer's acid carmine. 



This method of spermatogenesis is normal to nemas. A large 

 number of species belonging to numerous and varied genera are 

 known to the writer in which the general appearances in the gonad of 

 the male so closely resemble those of Spirina parasitifera as to leave 

 him no doubt that the details of their spermatogenesis will show the 

 features here described, or something similar. The formation of the 

 spermatidian tissue is not an essential feature; in others of the above 

 species the spermatidia may remain separate. 



Current postulates must be modified in order to account for heredi- 

 tary transmission in this and similar animal species. The factors 

 usually believed to reside wholly, or in part, in the chromosomes 

 must here, in order to accord with the usual theories of heredity, 



