262 WILBUR WILLIS SWINGLE 
like 'tailed cells,' and in the writer's experience they occur rather 
infrequently, although on theoretical grounds one would expect 
to find them numerous. In 'tailed cells' the centrosome, instead 
of fragmenting or forming a multipolar spindle, sends out a long, 
somewhat spiral filament that grows outside the cell like the axial 
fiber of a spermatid. These filaments are extremely delicate struc- 
tures and difficult to make out. The stage at which these axial 
fibers grow out from the centrosome may vary somewhat. In figure 
23 the filament had evidently formed during late diakinesis, as 
there is a nuclear wall present. Figure 22 shows the fiber extend- 
ing out from the periphery of the nucleus — an unusual condition. 
Some of these figures correspond to, in fact are practically identi- 
cal with, Broman's ('00) drawings of giant spermatids in adult 
Bombinator ingenus material. Compare my figures 22 and 23 
with his figures. 
The type of cell represented in these figures is very abundant 
in larval material, especially following the period of greatest abun- 
dance of aberrant spermatocyte divisions. Not all such cells show 
axial filaments, indeed, they are rare. Such cells with filaments 
growing from the centrosome may be regarded as giant spermatids 
resulting directly from transformed first spermatocytes which have 
not undergone either first or second maturation division. Compar- 
ison of the stages figured in plate 13 brings out this point clearly. 
The same type of cell but without axial filaments is quite abun- 
dant; these originate in the same manner as described above, but 
cannot be spoken of as spermatids in the absence of the axial 
fibers. Broman has observed several filaments growing out from 
a single cell in his adult toad material ; so far such cases have not 
appeared in my material, and it has been a source of some wonder 
on my part why such cells are not of greater frequency. Cellu- 
lar conditions in the first-season larvae are ideal for the devel- 
opment of such structures in abundance. The relative infre- 
quency of the tailed cell may perhaps be correlated with the 
fragmentation of the centrosome. 
The giant spermatids are non-functional and usually undergo 
no further metamorphosis, but degenerate and are resorbed. 
Stages in the process are shown in figures 103 to 110. In very 
