THE EFFECTS OF HYPERTONIC SOLUTIONS. 
459 
(2) Effects of Hypertonic Solutions upon the Eggs 
of E. acutus. 
Series B. — Eggs treated one hour after fertilisation with 
50 c.c. sea- water + 6 c.c. 2| M. solution for 30 minutes. 
This series of eggs shows a marked difference to the eggs 
of E. esculentus which were subjected to exactly similar 
treatment. Whereas in E. esculentus there was always one 
definite vesicle to be found in each nucleus^ in E. acutus 
there are several. These are exactly similar in appearance 
and behaviour in the two species^ being’ either omitted or 
included in the daughter-nuclei of the first segmentation 
division. As a rule the vesicles are either four or five in 
number for each mitotic figui-e, and one or two of them are 
conspicuously larger than the rest. ThiSj however^ is not an 
invariable rule, as figures have been found with four large 
vesicles all about the same size. 
Like those found in the corresponding series of E. escu- 
lentus eggs, these vesicles stain pink in Erhlich-Biondi- 
Hedeiihain's stain. Their origin in these eggs is, however, 
diffei’ent. Numerous fused male and female pro-nuclei have 
been examined without detection of vesicles (tig. 34) ; on the 
other hand, in a few such nuclei well-formed vesicles are 
present (fig. 35). As, however, every astral figure seen (and 
these were very numerous) possessed well-defined vesicles, 
we cannot well attribute the origin of all these from the reti- 
culum inside the nuclear membraue. 
Fig. 47 shows individual vesicles considerably magnified, 
and their shape, together with the fact that many intermediate 
conditions between fully formed vesicles and normal chromo- 
somes can be found, at once suggested that they have been 
formed in such a way as are the vesicles in the hybrid eggs 
E. esculentus ^ x E. acutus ? (Doncaster and Gray 
[2]) : in other words, it is absolutely certain that the 
majority of vesicles in these eggs are derived 
directly from the chromosomes. This being so, we 
should expect to find a reduction in the number of normal 
VOL. 58, PART 3. — NKW SERIES. 31 
