HISTOLOGY OF THE LAND-PLAJSTAEIANS OF CEYLON. 
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the point (O) it divides into two, which, pass one on each side of the sheath 
of the pharynx, and from this point backwards to the very extremity of the 
body the digestive tube is double. A stout median septum intervenes between 
the two tubes in the posterior part of the body, and being prolonged upwards 
splits, as it were, into two to form the investing sheath of the generative 
organs (G) and the pharynx (PH.). Just above the pharynx and below the 
generative organs, on the left-hand side of the drawing, are seen indicated the 
openings of the lateral diverticula into the main digestive tubes. The pecu- 
liarly elongated pharynx (PH.) communicates with the tube by the small 
aperture (O). The small oval mass consists of the penis and uterus with their 
immediate investments. 
d. Digestive tube. 
PH. Pharynx. 
O. Opening of pharynx into digestive tube. 
G. Small mass containing penis and uterus. 
Pig. 3. Diagram representing the various organs, their relative positions and dimensions, 
of Rhynchodemus Thwaitesii , supposed to be seen from beneath, enlarged 
four diameters. Though the anterior extremity of the body is considerably 
broader than the posterior, the body is seen to run more abruptly to a 
point at the anterior than at the posterior extremity, a sort of shoulder 
being formed at the point where the sides of the body bend inwards to form 
its apex. 
This difference of form between the two extremities is always marked in 
specimens preserved in spirits. The digestive tract in the anterior part of the 
body exists as a single median tube, with a series of lateral caeca or diverticula 
opening into it on either side; these are indicated by the faint transverse 
lines, as is also their arrangement at the anterior and posterior extremities of 
the body. The median tube divides into two, to pass on each side of the 
capsule of the tubular pharynx, and remains double henceforth, embracing 
the capsule of the generative organs in like manner. Anteriorly is seen the 
single pair of eyes. The penis is represented as opened by horizontal section. 
The oviducts are observed to pass from the inner sides of the ovaries. 
E. Eyes. 
OY. Ovaries. 
D. Digestive tract. 
T. Testis. 
OD. Oviduct. 
O. Opening of pharynx into digestive tract. 
M. Indicates position of mouth. 
PH. Pharynx. 
A. K. Azygous seminal reservoir. 
