March, 1958]
A.
G.
SATHYANESAN
15
Pre-spawning phase
Pars anterior. It is the smallest component of the pars glandularis during this
phase. Acidophils, chromophobes and lilac basophils are the cell types present.
The acidophils may be irregularly round or angular and granulated (Plate I, Fig. 2).
Occasionally deep staining acidophils are present in the pars nervosa ramifications
of the pars anterior. The chromophobes resemble an assemblage of round nuclei
due to their scanty non-granular cytoplasm and ill-defined cell, limit (Plate I, Fig.2)
The lilac basophils are of the size of the acidophils and are generally restricted to the
region of the pars nervosal branches and some of which show signs of degeneration.
Sometimes few of these cells are also seen in the pars nervosa. The lilac basophils
may be the amphiphils described by Bell [1938] and Levenstein [1939] in the gold-
fish. But Scruggs [1951] reports that the amphiphils of the above authors [Bell,
1938, and Levenstein, 1939] are nothing but the acidophils. Apart from these
cell types, often groups of basophils resembling those of the ubergangsteil are also
present in the pars anterior (Plate I, Fig. 2).
Ubergangsteil. This lobe contains acidophils, basophils and chromophobes.
The acidophils are granulated and have round nuclei with prominent nucleoli (Plate I
Fig. 4). These have an average diameter of 18.9µ. The basophils are granular and
have an average diameter of 19.3µ. The basophils lack distinct cell limit. During
the later part of the pre-spawning period, few basophils with bluish orange globular
cytoplasmic inclusion are encountered. The term ' globular basophil ' as used by
Copeland [1943] and Scruggs [1951] to describe such basophils is adopted in this
work. Occasionally few globular cell inclusions are extruded and they are inter-
cellular in occurrence. Chromophobes are few and show no departure from that of
the pars anterior and have an average diameter of 10.2µ. The average percentages
of the basophils, acidophils and chromophobes are 51.8, 34.7 and 13.5 respectively
(Table I).
Pars intermedia. It is the largest component of the pars glandularis during
this phase. The main trunk of the pars nervosa arborises in its substance. The
pars nervosa branches have a fair amount of blood vessels and colloid-like material.
The acidophils, chromophobes and basophils are the types of cells present. The
acidophils form the chief cell type and are globular or ovoidal with distinct granulated
cytoplasm. The chromophobes look like naked nuclei due to their scanty non-
staining cytoplasm. Basophils are few resembling to a large extent, those of the
ubergangsteil and lie adjacent to it.
Pars nervosa. The pars nervosa during this period lodges colloid-like bodies
in the main trunk and in its branches ramifying the pars intermedia. These bodies
may be acidophilic or basophilic or polychromatic to staining reaction (Plate I,
Fig. 3). Generally they are granular, but homogeneous nature is also not uncommon.
Spawning phase
Pars anterior. The pars nervosa branches of the pars anterior are devoid of
glandular cells. The lilac basophils are well defined. In other respects this
component resembles that of the pre-spawning phase.
Ubergangsteil. This lobe increases in its bulk at the expense of the other two
glandular components lying on the dorsal and ventral sides. The average percent-
age of the acidophils is reduced to 26.2 and they have an average diameter of 19.3µ ;