194 Records of the Intian Museum. [Vor Valk, 
intestine. The ventral surface is concave and rests on the 
penial sheath. 
Minute structure (pl. xxvi, fig. 21).—The gland is composed of 
a number of lobules held together by connective tissue, which 
forms a thin sheath round the whole gland and aiso extends 
between the adjacent lobules. Each lobule is oval in shape and 
gives rise to a duct of its own which unites with others from 
the adjacent lobules to form the main duct of the gland. The 
lobular ducts could be distinctly followed to the oviduct by the 
naked eye. Each lobule consists of a single layer of flattened 
epithelium supported on a thin layer of connective tissue 
(forming the wall), witha central cavity filled with mature ova 
and spermatozoa. Each lobule gives origin to both ova and 
spermatozoa from its wall. 
In the formation of an ovum, a cell of the wall enlarges and 
becomes fusiform in shape; its free surface is covered by a 
single layer of flattened cells continuous with those of the wall 
of the lobule. When mature the ovum seems to lie free in the 
cavity of the lobule. 
The cells which ultimately form the spermatozoa seem 
to divide into a number of round cells (primary sperm mother 
cells) which become aggregated on the surface of conical or 
round projections into the cavity of the lobule from its wall. 
In a section of the lobule one will see several projections, the 
centre of which consists of a mass of protoplasm with a large 
nucleus. The primary sperm-mother cells are arranged on the 
surface of the projections. What seems to occur is the pro- 
liferation of an epithelial cell so as to form a mass of round 
cells on the surface of one which grows more rapidly than others 
and forms the supporting cell. The protoplasm of this cell is 
highly granular, and it has got no distinct cell-wall. The primary 
mother cells seem to divide again to form groups of secondary 
sperm-mother cells for by careful examination of stained sections 
under the microscope one will find a second set of smaller cells 
grouped in a similar way and still attached to a supporting cell. 
The nuclei of these secondary sperm-mother cells become gradually 
elongated to form the head of the spermatozoa. The different 
stages of the change in shape of the round nucleus to a rod-shaped 
body could be easily followed in stained sections. The proto- 
plasm of the cell then elongates to form the tail of the spermato- 
zoon. The mature spermatozoa then separate from these papillae 
and lie freely in the cavity of the gland in bunches. 
The mature ovum (pl. xxvi, fig. 22) is completely surrounded 
by a single layer of flattened cells (with distinct nuclei) attached end 
to end. The protoplasm is coarsely granular. The large nucleus 
lies in the centre and presents a conspicuous nucleolus. 
The mature spermatozoon (pl. xxvi, fig. 23) consists of a hook- 
shaped head and a long fine tail. The head is curved and pointed 
at the tip, but broad and rounded at the base. It is also curved 
twice before it ends in the tail, which is many times longer than 
the head. 
