64 THOS. H. MONTGOMERY jr., 



postsynapsis. In the first of these the 14 chromosomes elongate and 

 become thread-like, until they have attained a length about equal to 

 the diameter of the nucleus. One of the 14 ceases to elongate at 

 this stage, and from now on acts no longer like the other chromo- 

 somes: this becomes the chromatin nucleolus, which from the stage 

 of synapsis on shortens until it acquires a spherical form. 



5) The synapsis is characterised by the grouping of the chromo- 

 somes near the centre of the nucleus, where they become so closely 

 arranged that individual ones can no longer be distinguished. The 

 chromatin nucleolus shortens and thickens. A true nucleolus first 

 appears closely apposed to the inner surface of the nuclear membrane, 

 so that it is probably of cytoplasmic origin. The idiozome forms a 

 compact mass at one point on the outer surface of the nuclear mem- 

 brane; in it may be found with great regularity one or two small 

 granules, which are probably centrosomes. 



6) In the postsynapsis stage the chromosomes separate from one 

 another, and have the appearance of long, nearly smooth threads; 

 their number varies from 3 to 6 in different nuclei, 3 or 4 being the 

 numbers most usually found. These 3 to 6 chromosomes were prob- 

 ably formed by end-to-eud coalescence of the 13 chromosomes of 

 the synapsis; thus in the synapsis occurred a reduction in the number 

 of the chromosomes, but a reduction to less than one-half of the 

 normal number (14). The true nucleolus gradually becomes detached 

 from the nuclear membrane. The chromatin nucleolus gradually 

 becomes spherical, and in some cases divides into two or more 

 portions. 



7) The telophase is characterised by the shortening and thickening 

 of the chromosomes, which now have an irregularly monilated ap- 

 pearance. The true nucleolus increases in size and wanders towards 

 the centre of the nucleus. The chromatin nucleolus has become 

 spherical, and is apposed to the nuclear membrane. The idiozome 

 substance commences to disperse over the surface of the nucleus. In 

 this stage and in the postsynapsis large groups of cell syncytia are 

 found, which are characterised by a large quantity of yolk and ab- 

 sence of demarcating cell membranes; these syncytia denote groups 

 of cells which have received an especially abundant nutritive supply; 

 they divide into smaller groups of two or three cells each, before 

 the rest stage, the latter cells developing perfectly normally. 



8) There are 6 follicles in the testicle, two of which contain 

 spermatocytes of about double the size of those in the other follicles^ 



