MADE AT THE PLYMOUTH LABORATORY. 269 
distinct and definite outline, and a refringent homogeneous interior. 
Occasionally a few granulations appear in its centre. The body is 
not much unlike a nucleolus, but the nucleoli, under the action of 
acetic acid, show internal vesicles and the vitelline body does not ; 
the latter has also a pale yellowish colour, while the nucleoli are 
colourless. 
Fie. 2. Fria. 3. 
Fic. 2.—Egg in the germinal ridge of Syngnathus acus examined fresh with addition 
of 1 per cent. acetic acid. Shows the vitelline body close to the germinal vesicle. 
Fie. 3.—Another egg in the same preparation, showing two vitelline bodies on 
opposite sides of the germinal vesicle. 
The most remarkable fact about the vitelline nucleus in the ova 
of the pipe-fish is that there are often more than one of them in a 
single egg, frequently two, and I have seen as many as four. In 
the latter case the four were in a cluster, as though produced by 
the division of one, but when there are two they may be both 
on one side of the germinal vesicle, or one on one side and one 
on the other (Fig. 3). Henneguy examined the ovary of the 
pipe-fish apparently only in sections, and would not be so likely 
in that case to recognise the presence of two vitelline bodies in 
one ovum. ‘I'he bodies can be well seen and studied in prepara- 
tions of portions of the germinal lamella mounted whole. My 
best preparation of this kind was fixed in a mixture of chromic, 
osmic, and acetic acid, and stained with hematoxylin. The presence of 
two vitellme bodies in some ova in this preparation is easily con- 
firmed, It should be noted that when two are present they are 
smaller in size than when there is only one, The structure certainly 
persists unchanged in ova in which yolk has begun to form, I 
have been able to distinguish it clearly in such ova of a diameter 
up to ‘29 mm., and in these it is unchanged, showing no signs of 
the conversion into a granular mass which Henneguy describes as 
commenced in ova only ‘06 mm, in diameter. The vitelline nucleus 
is entirely unstained and homogeneous, and has an appearance very 
different from that of the nucleoli, which are somewhat shrunken, 
