12
INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY
[VOL. XXIX, PART I
Pfenderinae, Pseudodiscus (with Pseudodiscus colloisini only) under Pseudodiscinae, have been
assigned to the family Cladorchidae [Southwell and Krishner, 1937], but the genus Hawkesius
(with Hawkesius hawkesii) is included under sub-family Wastsoniinae [Nasmark, 1937] of the
family Diplodiscidae [Skrajahin, 1949]. Nickel [1949] found two types of trematodes in the
intestine of an Indian elephant autopsied after being 20 years in Europe and one of these he
has described as a species of Hawkesius (this paper was not accessible). Mudaliar and
Alwar [1947], in their check-list of parasites, have recorded from a elephant, Gastrodiscus
aegyticus [Cobbold, 1876], Pseudodiscus hawkesii and Pfenderius papillatus. Ramanujachari and
Alwar [1954] recorded Gastrodiscus secundus from large intestine of elephant.
The above review would indicate that there is some amount of difference of opinion, not
only, on the validity of some genera but also in the assignment of these under major groups of
classification. Moreover, there still appears certain degree of discrepancy in the description
and diagrams of the species. It is, therefore, proposed to describe briefly the salient features
of the specimens collected which belong to Pfenderius papillatus (fig. 1), Pfenderius heterocaeca (fig.3)
and Pseudodiscus hawkesii (fig. 4). These have mainly been studied for indicating the useful
criteria in differentiating these and the inaccuracies that are discernable in the accounts and
illustrations available in the literature. The question of validity of some of the species and
genera would likewise be dealt with in the present note.
PFENDERIUS PAPILLATUS [Cobbold, 1882; Stiles and Goldberger, 1910]
Only one specimen of this species is among the entire collection. It had a slightly pinkish
colour, an oval shape with the anterior part capable of much movement and a convex dorsal
and slightly concave ventral surfaces. In the stained preparation, the length is 4.6 mm.
and breadth is 2.9 mm. with the maximum breadth in the middle of the body length.
The oral sucker is subterminal, 1.0 × 0.8 mm. in size, and provided anteriorly with
frill of digitate papillae around the mouth, the central papillae being of bigger size. It has
in its mass a pair of lateral pouches or diverticula (pharyngeal sacs) and leads into the oeso-
phagus, 1.0 m.m. in length, with a thick wall and well-developed muscular posterior region
before it branches into two intestinal caeca. The caeca are wavy in outline showing mainly
externally a few sacculations or 'diverticula' and extend posteriorly to near the anterior limits
of acetabulum, which is subterminal, 1.4 mm. in diameter and provided all over on its internal
aspect with well developed and prominent papillae arranged uniformly and concentrically.
The common genital pore (fig 2), with a prominent genital atrium, lies at the level of the
intestinal bifurcation. The ovary, 0.3 mm. in size, is of oval shape with smooth margin and lies
immediately in front of the acetabulum with Mehlis gland on its latero-posterior aspect and with
the first coil of uterus inside its mass and between it and the ovary. The main mass of uterus
then pursues a central course in closely packed coils, with only 2 eggs in the preparation,
lying between the testes and leading into a prominent meteraterm which travels side by side
with the terminal part of the cirrus sac to open into the genital atrium. The size of the eggs
cannot be indicated as both the eggs had undergone distortion during staining and mounting.
Testes, with a slightly lobed character, are preovarian and symmetrically situated, one on either
side just in the middle of the body. The cirrus sac is muscular, pear-shaped with a similarly
shaped seminal vesicle, which does not have a coiled character and leads into pars prostatica
and a well-developed ejaculatory duct.
Westhuysen's account of the species is according to Stiles and Goldberger and differs
in a few points from the foregoing short description in respect of the oral papillae, the aceta-
bulum, character of intestinal caeca and that of the seminal vesicle. The acetabulum has
been described with its opening directed slightly ventrally, the intestinal caeca with a slight
cephalic curvature before terminating and the seminal vesicle as a coiled duct. Further,
the diagram of the whole mount, that is from Travassos after Stiles and Goldberger, does not
give a clear picture of the position of the common genital pore, structure of cirrus sac and
finally the course of the terminal parts of the reproductive ducts.
The specimen at our dis-
posal, however, on the general topography is assignable to the species, P. papillatus, and the