HISTOLOGY OF THE L AXD-PLANAEIAX S OF CEYLON. 
151 
mainly occupied by radiating muscular fibres, prolongations of the circular 
muscles surrounding the viscera. It contains, interspersed in its substance, 
gland-cells containing rod-like bodies and pigment-cells. The longitudinal 
muscles, having been exposed in section to the action of carmine, are readily 
recognizable by the deep tint which they have taken, and may be seen to be 
specially developed (I. L. M.) along a line reaching to the region of the testes 
and water-vascular trunk of either side, from a point a little way internally to 
the lateral border of the animal. Opposite the lateral borders of the animal’s 
body these muscles are sparingly developed ; inferiorly, again, on either side, 
to the commencement of the intestinal diverticula, they are aggregated in 
considerable masses. The superficial muscular layers are largely developed 
along the median dorsal and infero-lateral lines. A collection of glandular 
tissue is seen on the outer side of either testis at X. 
D. Central gastro-intestinal canal. 
D'. Lateral diverticula given off from central canal, D. 
E. Epidermis. 
P. Pigment. 
E. C. M. Exterior muscular layer, consisting of circular and decussating 
fibres. 
E. L. M. External longitudinal. muscular layer. 
I. L. M. Internal longitudinal muscular layer. 
L. M. External longitudinal muscular layer in the ambulacral line. 
P. M. Zone occupied by radiating muscular fibres, and containing also 
glands, Stabchen-Organe , and pigment-cells. 
OD. Oviduct. 
V. D. Yas deferens. 
T. Testis. 
W. Water-vascular trunk. 
X. Aggregation of glandular cells. 
Pig. 6. Vertical section of Bipalium Ceres , taken in a direction transverse to the long 
axis of the body, at a spot about half an inch distant from the anterior margin 
of the animal’s head. Drawn with the camera lucida. The form of the body 
is seen to be very different from that of JB. Diana (see fig. 5, Plate X.), and in 
some respects to approach that of JBJiynchodemus. The points A, A correspond 
to the ridges characteristic of this species, which run along the body inferiorly 
on each side of the ambulacral line, and which contain masses of finely gra- 
nular material, A, A, from which tracts of glandular matter lead to a point 
just above the testes. The ambulacral line projects less than in Bipaliuni 
Diana ; the oviducts are lower in position than in that species, lying within 
the water-vascular trunks. The external circular and longitudinal muscular 
systems are greatly developed in the dorsal region. 
