84 THE ANATOMY OF AN AUSTRALIAN LAND PLANARIAN. 
A short distance behind the external genital aperture the two oviducts turn 
inwards and unite together (Fig. 43, odd.) The united oviducts then open into a 
small dilated chamber (Fig. 48, a.), and this latter communicates with the posterior 
end of the uterus by means of a short, narrow duct, which runs upwards and forwards, 
as shown in the figure. The small chamber and the duct leading thence to the 
uterus are lined by very narrow, elongated, columnar, ciliated cells. Lying around 
the dilated chamber and converging towards it is a quantity of feathery-looking tissue, 
the structure of which is difficult to make out and requires further elucidation. 
This tissue is characterised by a very distinct, yellowish-brown colour, which it 
retains even in deeply stained sections. It probably forms an accessory gland of 
some description opening into the chamber by numerous very fine ducts. Moseley 
(6) figures accessory glands somewhat similar in appearance opening into the uterus 
in Bipalium. 
(c.) The Uterus and Vagina.—These organs are enclosed in a dense muscular 
mass of the shape shown in figure 32, which is easily dissected out as a distinct 
structure and may be called the female copulatory organ. The broader and more 
posterior part of this structure is the uterus, which gradually tapers off in front to 
form the vagina, which curves forwards and downwards to the external aperture. 
The muscle fibres around the uterus and vagina are principally disposed in a circular 
direction, but numerous longitudinal fibres also occur. The longitudinal fibres occur 
principally in a fairly well-defined layer on the inside, surrounded by the much 
thicker layer of circular fibres. Imbedded amongst the muscle fibres, chiefly around 
the uterus, numerous darkly stainmg granular bodies appear, closely resembling the 
mucous glands. They are probably accessory glands which secrete the mucous 
which is always found within the cavity of the uterus. 
‘The cavity of the uterus is lined by a very peculiar epithelium, which is shown 
in figure 33. This epithelium is composed of richly ciliated columnar cells, and its 
peculiarity consists in the presence of innumerable slender, elongated villi, composed 
entirely of the ciliated columnar cells and projecting into the cavity of the uterus. 
Anteriorly the lumen of the uterus gradually diminishes in diameter to form that 
of the vagina, and at the same time the villi disappear and give place to a smooth 
lining epithelium composed of a single layer of richly ciliated columnar cells. 
The vagina opens into the common atrium genitale, which, as I shall show 
later on, is so small and rudimentary that it is often hard to distinguish at all. 
The form and relations of the female copulatory organs, the mode of opening 
into them of the oviducts, and the histological structure of the uterus differ very 
markedly in Geoplana spencer: from what has been described by Moseley and von Kennel 
in the forms examined by them, as will readily be seen by comparing the works of 
those authors. 
