138 
MR. H. N. MOSELEY ON THE ANATOMY AND 
ova, which are driven forwards by muscular pressure, from making a retrograde motion. 
The exact connexion of the oviduct with the cavity of the ovary in Bipalium could not 
he determined : it was only traced as far as is figured (Plate XIII. fig. 8), where the 
oviduct is seen to expand as it passes about halfway up the outer side of the ovary. In 
Bhynchoclemus the oviduct was found to take origin from a papilla on the upper and 
inner side of the oviduct, and projecting into its cavity (Plate XIII. fig. 13). The papilla 
is formed of spindle-cells, and a number of similar cells are to be found scattered in the 
loose tissue around its base. The oviduct passes up through the loose external capsule 
of the ovary, and lies externally to the membranous internal capsule. The oviducts are 
directed in straight lines down the body, and passing just externally to the sheath of 
the pharynx reach the region of the uterus, to which organ they are directed by a sharp 
turn inwards (Plate XII. figs. 1 & 6). In Rhynchodemus the ducts are directed at first 
a little obliquely outwards to reach their position immediately internal to that of the 
vasa deferentia. In both Bipalium and Rhynchodemus the oviducts are crossed in the 
lower part of their course by the vasa deferentia, which pass to the dorsal aspect of 
the ducts. In Bipalium this crossing takes place about the region of the oral aperture ; 
in Rhynchodemus lower down, opposite the base of the penis. In Bipalium, in the region 
occupied by the posterior portion of the pharynx, and from thence to the uterus, the 
oviducts have connected with their external aspect on each side peculiar branches or 
diverticula. These diverticula are very short, and are all directed at a slight angle 
backwards, i. e. towards the animal’s tail. There are about six of them on each side, 
and they are situated at tolerably regular intervals. One of these diverticula is seen 
highly magnified in Plate XIII. fig. 9. A short branch is seen to enter the oviduct at 
an angle. The branch is constructed in the same manner as the oviduct itself, and has 
its cilia directed inwards towards the cavity of the duct. It ends abruptly, as far as 
definite oviducal structure is concerned, but from its abrupt termination is prolonged 
an interlacement of connective-tissue fibres, forming a sort of tube or cavity. There 
can be no doubt that these branches here described are the rudiments of the branched 
ovary possessed by lower Planarians, such as Bendrocoelum lacteum. In Bipalium a 
single one of the branches, the most anterior or terminal one, has become enlarged 
and differentiated, and has taken on the whole of the ovarian duties : the remaining 
branches are present in a rudimentary condition, like the yelk-glands : in Rhynchodemus 
both diverticula and yelk-gland have disappeared. Our Land-Planarians are, in fact, 
in their ovary just like Polycelis cornuta, O. Schmidt (Dendrocoelen Strudelwurmer, 
Taf. iii. fig. 1). The position of the oviduct, as seen in transverse vertical sections, 
is of great importance : it is always in close relation with the main trunk of the 
primitive vascular system, lying immediately above it or just within it in B. Ceres, and 
slightly externally to its median vertical line. This position holds good throughout the 
course of the oviduct in Bipalium, Rhynchodemus, and., singularly enough, in Bendrocoelum 
lacteum also (Plate XIV. fig. 7), showing how closely related are all the forms ; and I 
was surprised to find in Bendrocoelum lacteum the oviduct so far histologically differ- 
