TUE SrEF.lIATOOENESIS OF DOIIESTIC JI.VMM.Uitj. 2J5 



(j. Ill the first division tlio cliromosomes arc divided along the conjugated 

 jiLtues ; thus the first division is a rodiieing one. In tlia second all tbo 

 cbromosDUKS become so placed that thoir longitudinal splittings c;)incide witli 

 the equatorial plane, and along this line all the chromosomes as well as the 

 XT iu-e divided at the samu time; thus the sscond division is an eqUiition 

 division. 



7. Tlie XY-chromosomes exist and cm be traced witli corbaiuty up Uj 

 the primary spermatocyte. 



8. The chromatoid Iwdy first ap^xsirs at the eai'ly pr-ophase. In the 

 reduction division tliis bod}- enters imdividod into one of the (Liughter cells 

 and disappsars in the " Sühwanzmansshetta " at the formation of the 

 speriiuitozoa. 



9. The mitoehondi'iiU granules appoar in the spsrmatocyte as well as in 

 the spermatogonia, but they inci-oase in number dming the gi-owth stage. In 

 the siiermatid they become arranged spirally around the axial filament. 



10. In the spermatogonia and the spermatocyte the (lentriisomes could 

 not 1)6 seen. Its Ijehavior in the developmant of the spermatozoa is almost 

 similar to the condition found by Duesberg ('08) in the rat. 



II. Observation in the Kabbit. 



1. The resting nuclei of the spcrmatogonial cells iisually contain many 

 cluümatin masses and several ni:cleoli. 



2. The number of siiermatogonial chromosomes is considerably varied. 



3. The resting primary sixsrmatcx^ytcs usually appear. 



4. In the synaptic stage the chromatin spiremes aggregated at one nuclear 

 pole wheiv the idiozome is sitimted. In this stage the parallel arrangement 

 of the chromatin spiremes is clearly to Ije seen. 



5. In the propliase several rlug-shaiied chromosomes appear which are 

 diiferont in apj^xaarance from tliose of the mouse. In this stage the numlKir of 

 chromosomes may be counted as twenty four. 



6. In the growth jieriod two or more nucleoli can usiTally be seen, similar 

 to those of the mouse in their behavior. 



7. Tlie first division is a nxluciug one and the second an equation. 



8. The cbromosDme nucleolus or the accessory chromosome can be traced 



