114 SPOLIA ZEYLANICA. 
much more lightly coloured. There are three black dorsal stripes, 
the medium one being narrower than the two others. On account 
of the deep ground colour on the greater part of the body the stripes 
are more Clearly defined at the two extremities, particularly at the 
anterior end, where the ground colour is much lighter. The colour 
of the ventral surface of the body is grayish, excepting a median 
colourless band represents the sole, which is slightly elevated. 
The sole extends almost the whole length of the body, but ends 
abruptly behind the ventral depression of the head-flap. Near its 
anterior end the sole is a little broader, so as to show a special area 
(see Plate IV., fig. 4) about 0-4 mm. long. Close to both lateral 
edges of this swollen area are two fine parallel ridges (see Plate IV., 
fig. 4). On examining the sections it is seen that these two ridges 
are ciliated, as also is the shallow groove between them. The mouth 
is a small elliptical slit near the middle of the sole. The genital 
opening is about 5 mm. behind the mouth. 
All three kinds of the “ Stabchen ” (von Graff) are met with in 
the epidermal layer. Rhammites and chondrocysts generally occur 
together, and are very widely distributed almost over the entire 
body-surface, excepting the sole and that part of the head-surface 
which lies above the brain and is dorsal to the horseshoe-shaped 
glandular ridge. The chondrocyst (see Plate IV., fig. 5, ch) isa rela 
tively large and oblong body, nearly homogeneous in structure, which 
is lightly stained with hematoxylin. It is found almost always 
surrounded by a number of long and slender rhammites (7m). The 
latter are easily distinguished from other “‘Stabchen’”’ by their 
thread-like shape and curled, pointed endings. In those narrow 
regions which are hemmed in between the sole and the glandular 
margins (inclusive of the ridge), the two ‘“‘ Staébchen ” are sparsely 
scattered, and the chondrocysts are rather indistinctly outlined (see 
Plate IV., fig. 8). The rhabdites are straight thick bodies pointed 
at both ends (see Plate IV., fig. 8, rd), and are moderately stained by 
hematoxylin, more lightly than the rhammites, but more deeply 
than the chondrocysts, so that they are readily distinguished. The 
rhabdites are remarkably scarce. They are only found in those 
regions which lie between the sole and the glandular margins, and 
extend posteriorly only as far as the ventral ciliated organs. They 
are never found in company with chondrocysts or rhammites. The 
presence of the three sorts of “‘ Stabchen”’ and the peculiar distri- 
bution of the rhabdites mark definite, though not very important, 
points of distinction between the present species and other members 
of the Rhynchodemide, since the latter, according to von Graff,* 
form a yroup in which the three “‘Stabchen” rarely occur together, 
and the rhabdites, if present, are usually scattered over the whole 
body-surface (as in Dolichoplana), or over both the dorsal and ventral 

* Von Graff, Ludwig 7 Monographien der Turbellarien, IJ. Triclada Terri- 
cola (Land Planarien). Liepzig, 1899. 
