J. A. Innes 
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examples (Fig. 1), to a short stumpy cone with a highly wrinkled surface 
(Fig. 2). In contracted examples the posterior sucker is reduced to 
about one third the diameter of the terminal area and retracted within 
it. A cross section through any region of the body appears to be circular. 
The mouth opens anteriorly (Fig. 1, M.) exactly at the apex of the cone, 
and is surrounded by a mass of muscular tissue. It may be used some¬ 
times for adhesion. Oral papillae are present. 
The transverse opening of the genital atrium lies a little behind the 
mouth in the mid-ventral line (Fig. 1, A.P.) and is easily made out in 
all specimens. It is lined internally with papillae. 
The large posterior sucker is placed terminally and when expanded 
occupies almost all the posterior portion of the parasite (Figs. 3, 4 and 5, 
P.S.). It seems to have a slight inclination towards the ventral surface. 
The ventral side is straight, or slightly concave. The dorsum is distinctly 
convex. 
Fig. 3. Fig. 4. 
Fig. 3. Terminal sucker of G. bubalis. 
Fig. 4. Longitudinal section through posterior end of G. bubalis. P.S. posterior 
sucker. 31.P. muscular part. 
Internal anatomy. The alimentary canal consists of the anterior 
terminal mouth, a muscular pharynx, and a short oesophagus which 
bifurcates on a level with the middle of the prostate gland, into the two 
limbs, or pockets of the gut. These limbs are blind sacs and pass down 
on either side of the atrium (Fig. 6, L.G.). They pass dorsal to the testes 
and terminate on a level with the middle of these organs (Fig. 5). The 
gut branches show varied convolutions. In some species of Gastrothylax 
the gut pockets do not reach the testes. The genital atrium is large 
and roomy and expands towards the posterior end where it terminates 
just above the anterior boundary of the testes. It is triangular in cross 
section with a ventrally directed apex (Fig. 6, At.). In certain sections 
through the atrium clots of organic matter have been seen, while in one 
case there was a single ovum. The physiology of this organ is at present 
unknown. It opens to the exterior at the anterior end on the ventral 
surface and in this region also receives the genital opening (Fig. 5, A.P.G.). 
