SPERMATOGENESIS OF SQUILLA ORATORIA ails 
As was pointed out by Binford (13) and Fasten (718), it is 
possible to distinguish primary and secondary spermatogonia, 
although the distinction between the two is not infrequently 
rather obscure. The former (fig. 3) are restricted to the pro- 
liferating region mentioned above, whereas the latter (fig. 2) 
are distributed throughout the remaining outermost zone of the 
testicular tube. Apart from this topographical distinction, the 
two kinds of spermatogonia differ in some structural details: 
the nucleus of the primary spermatogonia is larger and more 
vesicular than that of the secondary and the karyosomes of the 
former are more regularly spherical. 
In the spermatogonial mitoses no continuous spireme is formed. 
The chromosomes ab origine are ovoid or ellipsoid in shape. In 
two fairly good equatorial plates (figs. 4 and 5) I was able to 
count forty-eight chromosomes. Between two adjoining chro- 
mosomes a linin strand is often detected. The chromatoid 
body (fig. 6, /) lies outside the spindle and enters one of the two 
daughter-cells without division. 
Interspersed between the spermatogonial and spermatocyte 
cells are numerous nutritive cells (fig. 1, nt, fig. 7). They show 
usually some degree of resemblance in appearance to the sper- 
matogonial cells, but may be distinguished by the fact that the 
nucleus stains somewhat darker by basic dyes and is usually 
irregular in shape: triangular, crescentic, sausage-shaped, or 
even with pseudopodia-lke projections. In some cases the 
nucleus exhibits an appearance highly suggestive of the occur- 
rence of amitosis. ‘The boundary of the cell is often difficult to 
detect; furthermore, not infrequently a group (three to five) of 
nuclei are embedded in a common syncytial mass. 
Among workers of decapod spermatogenesis, the origin of 
spetmatogonial and nutritive cells has been a matter of great 
dispute (Fasten’s paper, 714). As to Squilla, Grobben (’78) 
points out the occurrence of ‘Ersatzkeim’ and Gilson (’86) speaks 
of “plasmodium pérphérique,’ both undoubtedly referring to the 
nutritive cells. However, concerning the question of their 
origins, they do not express any definite opinion. I could 
likewise obtain no data to decide the question, but this much 
