154 J- Moore, 



iwocess of fusion heUveen the individiial globules in the cloud it first 

 produced. The centre of each globule presents a small dark particle 

 (Fig. 17), and it is probable that these particles exist from the very- 

 first — because, so soon as they come into view, they continue to grow 

 in proportion to the globules that contain them. As the size of these 

 globules augments and their number decreases, they assume the appea- 

 rance of small vesicles, each with an enclosed dark body, the whole 

 archoplasm at last becoming like a mulberry, studded with warts. 

 I propose to call the globules from their first appearance archoplasmic 

 vesicles and their contained bodies archosomes (as). 



The process of fusion continuing among the vesicles, there is left at 

 last but one large vesicle and one large archosome (Figs. 18, 19). The 

 undifferentiated portion of the archoplasm (that which remained between 

 the globules during their formation) is now seen to be collected on the 

 exterior of the archoplasmic vesicle, i. e. on the side remote from the 

 nucleus. At first sight the cells appear to have an archoplasm which 

 is now quite detached from the nuclear membrane, but on closer in- 

 vestigation, the intervening space is seen to be occupied by the archo- 

 plasmic vesicle and archosome. 



The apparent detachment of the archoplasmic remains from the 

 nucleus ultimately becomes a real one. The residual mass, which I 

 propose to term the residual archoplasm, wanders back into the cell 

 body, where it ultimately becomes definitely oriented with respect to 

 the tail and certain structures which I shall describe (Figs. 22, 24, 25). 

 The archosome sometimes appears to be in connection with the residual 

 archoplasm, long after the separation of the residual archoplasm from 

 the nucleus has become practically complete (Fig. 9). The subsequent 

 behaviour of the archoplasmic vesicle seems to be somewhat different 

 in different types. In the rat, the structui-e almost disappears (Figs. 21, 

 24, 25) leaving the archosome as a little wart on the nuclear circum- 

 ference (Figs. 20, 21 a .s), which flattens out into a sort of expanded 

 "cephalic cap" upon that part of the nucleus which ultimately becomes 

 the extreme point of the spermatozoan head. 



In the rabbit, the vesicle persists much longer, its inner wall be- 

 coming closely applied to the nucleus; and, as development proceeds 



