THE SPERMATOrJENESK OF DOMESTIC lIA.MiI.UiS. 219 



136). Sx)n nftor tliis Ixidj grddiially diniiuishcs in size, but Ix-iug deeply 

 stainal with acid-fuchsin, it c.in asiuilly he seen until tlie time of the dis- 

 appearance of the nuclenr wall (Fig. 138). When the nuclear membrane 

 begins to disintegrate, the nucleolus except in soaio raro^cases, can not be seen 

 (Figs. 37, S8). 



The niitochondriiil granules, are now considerably increased in number 

 as compared ^\ith previous stages (Fig. 26). At the late prophase when the 

 nuclear wall bqjins to disappear, (ho idiozomo completely disappears, but tli(3 

 chroma^oid body cjin sometimes bo seen clearly in the cytoplasm. 



B. Tlie gi'owth period of the spermatocyte of the rabbit. 



TIxe resting s'age : — Tlie resting spermatocytes are found always in 

 contact with spermatogonia ,in"anged directly within the wiiU of the tubule. 

 The nuclei usually contain, like those of the resting s^x^rmatogonial cells, many 

 chromatin masses and several nucleoli (Fig. 146). Regarding the chromatin 

 nucleolus, no phenomenon of dimorphism is to be observed in this stage. 



Tlie leptotene stage:— The chromatins soon condense into apparently 

 continuous, slender filaments (Fig. 96). Tlicse immediately begin to converge 

 to oae- pole of the nucleus where the idiozome is situated. Dm-iug tliis stago 

 the chromatin threads become aiTanged in a tangled mass, but no parall(>l 

 aiTangement can Ixs seen (Fig. 96). 



The synaptic stage: — Following upon the leptotene stage comes the 

 synaptic stage. As in the hor.se the leptotene tlu-eads become aggi-egated at 

 one jxjle of the nucleus where the idiozome is situated (Fig. 97). Finally the 

 spiremes are gathered together and form a mass, but, by careful observation, 

 their individimUty can clearly bo made out (Fig. 98). With the aggregation 

 of the chromatin spiremes the nuclear wall expands rapidly, leaving a clesxr 

 space on the other side of the nucleiLs (Fig. 97-93). At the end of thir, 

 stage the parallel arrangement of the spiremes em very often be seen. The 

 whole mass of the chromatin threads begins to move towards the center of 

 the nucleus, the clear space thus gradually disappearing, while the nuclear 

 wall becomes spherical (Figs. 99, 100). 



As in the guinea-pig described by Duesbeuc, ('11) the mitochondrial 



