560 
j. br*ont£ gatenby. 
thinks the germinal epithelium is a syncytium, but as he 
uses Zenker for fixing this is almost certainly due to the 
brutality of fixation. Buresch gives a fairly good account of 
the generations of egg-cells, nurse-cells, etc., and shows 
how the presence of a large egg affects the surrounding cells. 
Concerning forms other than Helix we have two late papers 
by Terni and by Schitz. The latter (5) on Columbella finds 
the Nebenkern rods in the spermatocyte at the beginning of 
growth, and in later stages they form a sort of palisade 
around the nrchoplasm (idiozome). In the prophases of the 
maturation mitoses these rods disappear. The mitochondria, 
before seed-like, become elongate as in the snail during 
mitosis. The Nebenkern in spermatogenesis becomes passed 
into the tail region where it “ ultimately degenerates/’ but 
the author does not pay much attention to late stages. 
Schitz somewhat obscurely describes the formation of an 
acrosome from a “ grain siderophile,” derived from the idio- 
zome (archoplasm), and to support his statement quotes 
Champy’s demonstration of the fact that in Amphibia the acro- 
some develops at the expense of one of the central corpuscles. 
I find it difficult to accept Schitz’s claim, and his figures are 
not conclusive enough. The mitochondria form a sort of 
double sac-like structure, “ envelloppant le filament axile.” 
Finally, Schitz speaks of the tail as “ constitute par le fila- 
ment axile, entoure de sa gaine mitochondriale.” It will be 
seen that, excepting the formation of the acrosome, the fate 
of the Nebenkern and its behaviour throughout, according 
to Schitz, corresponds to what happens in Helix. 
Tullio Terni (6) in Geotriton carefully describes Nebenkern 
and mitochondria. In divisions the Nebenkern fragments or 
completely loses its original character. Terni having described 
the fragmentation of the batonettes proceeds to discuss the 
question as to the origin of the spindle. Nebenkern and 
idiozome seem synonymous to him, for I find “II Neben- 
kern dei Gasteropodi polmonati (Idiozoma).” He says : 
“ Sostenendo l’origine endoidiozomica (Terni calls the 
batonettes ‘formazioni periidiozomiche/ and elsewhere 
