582 
J. BRONTE GATENBY. 
the case may be. I do not fail to recognise the splendid 
labours of such observers when I state that I cannot 
accept anything in their descriptions of such changes. There 
may be very slight differences, but I have failed to find any 
upon which one could reliably base a dogmatic statement. The 
differences between the individual behaviour of the chromatin 
in the nuclei of a number of progerminatives of the same 
probable future sex, are so wide as to cover the statements 
depending on size, staining power, and arrangement of chro- 
matin lumps, upon which these descriptions are based. 
To return to the cells which I have mentioned as about to 
undergo mitosis, Text-fig. 3, ii, S.P.P., shows a section 
through a region from which male cells were appearing when 
the snail was killed. The cell S.P.P. is leaving its place in 
the epithelium marked L and is pushing out. This cell has a 
nucleus, oval in shape and containing its chromatin in faintly 
staining lumps. There is a cloud in the cytoplasm containing 
dark bodies (PL 34, fig. 49). Inspection of Text-fig. 2 at the 
figure 2 shows another cell, but in a different locality, free 
Text-fig. 4. 
Fig. i. — Shows dropping off of the male cells, about to finish growth 
stage. At Y. the cell is becoming detached, at X. it is already in 
the lumen. The cell Z. may belong to this generation, or from the 
generation to which the boquet stages ( BS ) are derived. There is 
generally a mixture of various generations in this lower region of 
the diverticulum. X 900. Fig. ii. — Bichromate smear of adult 
sperm head. A. = acrosome, N. = nucleus, C. = centrosome, 
M. = mitochondrial sheath. Iron hsematoxylin. x 2000. Fig. iii. — 
Group of metamorphosing spermatids showing definite position of 
Nebenkern ( N.K . ). Also the curious arrangement of two granules 
(0.) where the hind centrosome lies. (Compare PI. 34, fig. 44.) 
X 1000. Fig. iv. — A spermatogonial group with Nebenkerne 
( N.K . ), spindle bridge ( S.B . ), mitochondria (M.), and a yolk cell 
(. NC .). (Compare PI. 29, figs. 1, 2, and PL 32, fig. 29.) Fig. v. — 
Several batonettes greatly enlarged showing difference in shape and 
size, and in one the relations of the archoplasm ( A.R .) with the 
inside of the batonette. (See Pl. 32, figs. 24 a and 25.) Fig. vi. — 
The large variety of Nebenkern rod at same magnification. (See 
PI. 33, fig. 36.) Fig. vii. — Three spermatogonia attached to a cell 
with a germinal epithelial nucleus, but with the cell granules 
grouped together at X. What these are, whether Nebenkern 
batonettes or mitochondria, was not ascertained, x 2000, 
