ON THE ANATOMY OF GASTRODISCUS HO MINIS 
The Ovary : — 
Approximately oval in shape, and slightly constricted in the middle, is 
much smaller than the testis, and lies slightly to the right of the middle line 
between the posterior testis and sucker. 
Situated dorsally, just behind the ovary, lies the well-developed shell 
gland. From the lower border of this Laurer's canal could be followed, 
opening after a short course dorsally (fig. 4). The uterine coils are situated 
dorsally to the testis, and could only be traced in the sections by the remains 
of broken-up eggs. 
The Vitellaria : — 
While in G . polymastos the vitellaria can be traced in sections as far for- 
ward as the genital pore lying external to the gut forks, and are massively 
developed posteriorly in the region of the sucker ; in those sections of G . 
hominis which were more or less perfect the vitellaria could only be traced as 
far forward as the anterior border of the posterior testis. In this case also 
the vitellaria were most developed posteriorly in the region between the 
posterior sucker and the termination of the gut forks (fig. 2). 
The Disc : — 
The disc in G. polymastos is covered with numerous papillae visible to 
the naked eye. On the summit Of these open a corresponding number of 
accessory suckers which, on cross section, show themselves as a number of 
tubes. In G. hominis there is no trace of these suckers. On the other hand, 
the cuticle over the ventral surface of the sucker is nowhere smooth as it is 
on the dorsum, but is thrown into a number of microscopic ridges, apparently 
caused by the disposition of the excretory tubules, which are very numerous 
in this position. These ridges are evidently not due to contractions of the 
cuticle, for they are quite unlike artificial papillae produced by contractions 
elsewhere. They show no signs of being perforated when cut transversely 
to the surface. 
G. hominis then forms no exception to the rule that the Par am phi 
stomidae possesses two testes. 
I have not considered here other details, especially the structure of the 
genital papilla and its appendages, owing to the imperfectly preserved state 
of the tissues. 
LITERATURE. 
(1) Amphistoma hominis: n.sp. A New Parasite affecting- Man. By T. R. Lewis, 
M.B., and J. F. P. McConnell, M.B., Proc. Asiat. Soc. Bengal, 1876, p. 182. 
(2) Leuckart. Die Parasiten des Menschen, Trematodes, p. 450. 
(3) C. v Lejtenyi Ueber den bau des Gastrodiscus polymastos Leuckart, mit drei 
Tafeln. Senckenberg : Natur. Gesell. Zwoelfter Bd. , pp. 125-146. 
EXPLANATION OF FIGURES. 
Fig. 1. — Ventral view: c.g.p., common genital pore; p.s., ventral sucker; d., disc. 
Fig. 2. — Schematic frontal section: ph.p., pharyngeal pouch; sph., sphincter; c.g.p., common genital 
pore; t.a., testis anterior; t.p., testis posterior; ov., ovary; sh.gl,, shell gland; vit. , 
Fig. 3. — Transverse section through pharyngeal pouches: ph.p., pharyngeal pouch; gang., oesophageal 
ganglion; oes., oesophagus. 
Fig. 4. — Transverse section in front of the posterior sucker: r., "ridges" on disc; ov , rvary : sh.g., shell 
gland; I.e., Laurer's canal. 
