170 
ME. H. N. MOSELEY ON THE ANATOMY AND 
numbered, commences from above. The distinctness and variety in size of the 
ganglionic cells is to be noted, also their disposition in a bilaterally symmetrical 
manner, and the complex arrangement of nerve-fibres passing between the 
several regions. 
A pair of accumulations of especially large cells (A, A) is to be observed 
(posterior aspect of the ganglionic masses) in figs. 1 & 2. The nerve-cells are 
disposed mainly at the periphery of the ganglionic mass, the central region 
being occupied by commissural fibres ; but a small aggregation of cells is seen 
amongst the commissural fibres at B. Well-defined transverse commissural 
fibres (C, C) connect the two halves of the ganglionic mass anteriorly and 
posteriorly. Connecting fibres run between the roots of the different nerves 
at the periphery of the central portion of the ganglionic mass. The central 
region is occupied by vertical fibres, here seen in section as dark specks : 
these vertical fibres are especially developed at D. 
Fig. 5. Portion of the network of the nervous system from the head of Bipalium Pro- 
serpina, as seen in a longitudinal section in the plane of the body, from a spe- 
cimen hardened in chromic acid. Drawn with the camera lucida. 
The network here represented comes into view in sections prepared from 
specimens hardened in chromic acid when these sections are stained with 
carmine, and conforms in position and ramification with the water-vascular 
system. Masses of finely granular matter are seen imbedded amongst the 
fibres at the nodes of the network. 
Fig, 6. One of the eye-spots of Bipalium Diana. The eye consists of a hollow cell of 
the shape here represented, the wall of which is pigmented posteriorly, but 
transparent anteriorly. There is a sharp line of demarcation between the 
transparent anterior and pigmented posterior portion. The pigment is present 
in the form of small rounded granules. An unpigmented spot appears to 
indicate a nucleus. 
Fig. 7 shows a section of the eye. The cell-cavity is seen to contain a lens-like body, 
here dark as stained with carmine. A highly refracting substance exists 
between this lens-like body and the pigmented wall of the cell. 
Fig. 8. Eye of Bhynchodemus Thwaitesii. The anterior transparent cornea projects 
through the epithelial layer of the animal’s body. A short filament is seen 
attached to the proximal extremity of the eye. 
Fig. 9. Small portion of the margin of a longitudinal section in the plane of the body 
of Bipalium Diana, from the region of the body just posterior to the semi- 
lunar anterior expansion. Drawn with the camera lucida. Superiorly is seen 
the epithelial layer (E), beneath which is the basement membrane (B) and the 
external circular muscular fibres (E. C. M.), here seen in transverse section; 
internally to these is the external longitudinal muscular layer (E. L. M.), here 
rather thin, and beneath these are the eyes (O). 
