148 
MR. H. N. MOSELEY ON THE ANATOMY AND 
posterior portions of the oviduct are the rudiments of a ramified ovary, such as exists 
in Dendroccelum lacteum. There are also glands present, which probably represent the 
yelk-glands and shell-making glands of aquatic Planarians in a more or less rudimentary 
condition. There is a comparatively simple penis and female receptive cavity in both 
Bipalium and Bhynchodemus. In Bipalium there is, further, a glandular cavity at the 
base of the penis (prostate). The organs described as nervous ganglia by Blanchard 
in Polycladus are almost certainly its testes and ovaries ; and therefore the arrangement 
of these bodies in Polycladus is the same as that in Bipaliwn. 
The chain of nervous ganglia described as existing in Bipalium ( Sphyrocephalus ) by 
Schmarda, and which has been referred to by so many authors, does not exist. There 
is no doubt that Schmarda mistook the ovaries and testes for ganglia. The real nervous 
system is ill-defined, but appears to consist of a network of fibres without ganglion-cells, 
which lies within the primitive vascular canals. In Leptoplana tremellaris the struc- 
ture of the ganglionic masses is remarkably complex in the arrangement of the fibres ; 
and well-defined ganglion-cells of various sizes are present and have a definite arrange- 
ment. 
Numerous eye-spots are present in Bipalium , most of them being grouped in certain 
regions in the head, but some few being found all over the upper surface of the body, 
even down to the tail. The eye-spots appear to be formed by modification of single 
cells. In Bhynchodemus two eyes only are present. All gradations would appear to 
exist, between the simple unicellular eye-spot of Bipalium and the more complex eye of 
Leptoplana or Geodesmus , where the lens is split up into a series of rod-like bodies, 
forming apparently a stage towards the compound eyes of Articulata. It is quite pro- 
bable that these compound eyes have arisen by such a splitting-up into separate 
elements of a single eye, and not by fusion of a group of unicellular eyes such as those 
of Bipalium. A peculiar papillary band runs along the lower portion of the margin of 
the head of Bipalium. The delicate papillae are in the form of half cylinders, ranged 
vertically side by side. Between the upper extremities of the papillae are the apertures 
of peculiar ciliated sacs. The papillae, from the mode in which the animal makes use 
of them, are probably endowed with a special sense-function. The sacs may have a 
similar office, or they may be in connexion with the primitive vascular system, and have 
an excretory function ; they may further be homologous with the ciliated tubes in 
Nemertines. 
In considering the general anatomy of Bipalium , it is impossible to help being struck 
by the many points of resemblance between this animal and a leech. Mr. Herbert 
Spencer has, in his ‘ Principles of Biology,’ placed a gulf between Planarians and 
Leeches by denoting the former as secondary, the latter as tertiary aggregates*. It is 
obvious, however, that a single leech is directly comparable to a single Bipalium. The 
successive pairs of testes, the position of the intromittent generative organs, the septa 
of the digestive tract, and, most of all, the pair of posterior caeca are evidently homolo- 
* The idea is that an Annelid represents a series of Planarians, or corresponding secondary aggregates. 
