HISTOLOGY OF THE LAND-PLAN ARIANS OF CEYLON. 
157 
P. Penis. 
PR. Prostate. 
V. D. Vas deferens. 
Fig. 7. Diagrammatic section of the generative organs of Rhyncliodemus Thwaitesii. 
The penis is seen contained in its spacious special cavity communicating 
by a narrow channel with a small cavity common to itself and the uterus, 
which cavity again communicates by a narrow opening with a third cavity, which 
opens into the external generative orifice. The pair of oviducts unite into a 
single tube, which passes up the back of the uterus to open near its summit. 
The muscular fibres and epithelium of the uterus are greatly thickened at its 
summit, forming a square-shaped projection into its cavity; this probably 
disappears when the uterus is distended either by ova or (to judge from the 
analogy of freshwater Planarians) by a capsule containing several ova, and is 
most likely due to the action of spirit. 
EX. External generative orifice. 
V. Vagina. 
C. P. Canal for penis. 
UT. Uterus. 
D. E. Ductus ejaculatorius. 
P. Penis. 
A. R. Azygos receptaculum seminis. 
V. D. Vas deferens. 
OD. Oviduct. 
T. Testis. 
Fig. 8. Terminal segment of generative organs of Dipalium Diana, enlarged five diameters. 
Beneath are seen the organs intact, above the same opened by vertical section. 
The rounded mass on the left contains the vagina and uterus, the elongated oval 
body on the right the penis. The capsules of the two bodies are intimately 
united, and the cavity containing the penis communicates exteriorly with an 
aperture common to it and the vagina. 
U. Uterus. 
Pr. Prostate. 
P. Penis. 
ex. External generative aperture. 
OD. Oviduct. 
V. D. Vas deferens. 
Fig. 9. Portion of a vertical section transverse to the long axis of the body of Dipalium 
Diana, passing through the external generative orifice. The cavity containing 
the penis is seen to open by a small aperture into the vagina. Above is the 
uterus, which turns off at right angles from the vagina. 
EX. External generative orifice. 
