WILCOX : SPERMATOGENESIS. 9 
scattered about the cell irregularly after the nuclear membrane degen- 
erates. Or the fragments may fuse into one mass, which subsequently 
breaks up. But quite often in Cicada the metamorphoses of these 
nuclei are rather regular, presenting stages very similar to those which 
the normal spermatid undergoes. Iam not aware that any one hitherto 
has suggested that the giant spermatozoa arise directly from sperma- 
togonia, and a priori it seems, I admit; quite improbable; yet my Cicada 
preparations point very strongly to this conclusion. 
CALOPTENUS FEMUR-RUBRUM. 
The testes of Caloptenus consist of tubular follicles, which lie closely 
packed together, parallel to one another. They are of nearly the same size 
throughout their length, being slightly larger near the blind end of the 
tubule, and tapering thence into the collecting duct, which opens into 
the vas deferens. In my Caloptenus material, taken in August and 
September, the spermatogonia were confined to a single compartment at 
the blind end of the tubule. After the spermatogonia the other stages 
follow in regular succession, a considerable part of the follicle being 
occupied by the prophases of the first division of the spermatocytes, 
Then follow regions in which the two successive cell divisions are taking 
place, then the spermatid metamorphosis, and finally the nearly mature 
spermatozoa, which with the degenerating cells entirely fill the lumen 
of the tubule. Figure 108 (Plate III.) represents a longitudinal section 
of a follicle, in which spermatogonia are shown at a, prophases of the 
first spermatocyte division at b, the first division at c, spermatids at d, 
immature spermatozoa at e, and degenerating cells at f. The stages of 
spermatogonia preparatory to division are seen in Plate IIT. Figs. 105— 
107, and Plate IV. Figs. 164—168.  Spermatogonium divisions are 
shown in Plate IIT. Figs. 119-121, 124, 131, 138, and Plate IV. Figs. 
169-171, and a tripolar division at Plate IV. Fig. 189. I could not 
determine how many divisions the spermatogonia undergo. The chro- 
mosomes in the prophases are twelve in number, twenty-four at the 
equator of the spindle, during metakinesis. The individual chromosomes 
are rod-shaped or often elongate spindle-shaped. In metakinesis they 
show ordinarily the well known V-shaped figures, and are connected with 
each other in pairs by means of linin fibres, The centrosomes are usually 
apparent (Plate III. Figs. 105, 132). Figure 105 shows the centrosome 
surrounded by a clear protoplasmic area. In most cases a nucleolus is to 
be seen during the prophases. In Figure 106 there is in the nucleus a 
body (nucleolus?) which seems to have recently divided. 
