Four New Diclidophorid Gill Parasites — Unnithan 
87 
HOST: Dussumeria hasselti Blkr., on the gills. 
LOCALITY: Trivandrum (southwest coast of 
India). Two specimens collected 27 November 
1954. 
DISCUSSION 
The genus Dussumericola possesses all the 
characters of the subfamily Choricotylinae, but 
at the same time it shows a number of unique 
characters which distinguish it from all the 
known genera included under the subfamily. It 
closely resembles Urocotyle n. gen. in many char- 
acters, especially in the structure of the clamps 
and the vagina, but differs from it in the shape 
and proportions of the body and in the absence 
of a terminal anchored lappet. Dussumericola 
approaches Diclidophora Dies. (Subfam. Dicli- 
dophorinae ) in shape, but differs in the structure 
of the clamps. Moreover, in Diclidophora a 
vagina is lacking, while it is present in Dus- 
sumericola. The new genus differs from Hetero- 
bothrium Cerf., 1895, in the absence of a long 
isthmus between the body and the haptor and 
in the presence of a vagina. It closely re- 
sembles Cyclobothrium Cerf., 1895, and Chori- 
cotyle Van Benden and Hesse, 1863, in a num- 
ber of characters, but differs from both in 
the presence of a vagina. The chief character 
which distinguishes the new genus from Dicli- 
dophoropsis Gallien, 1937, is that the latter pos- 
sesses a double lateral vagina. The resemblance 
between the present species and Echinoplema 
Raecke, 1945, is more pronounced: in both the 
haptor is demarcated from the body by a promi- 
nent lateral constriction, the clamps have mus- 
cular pads, a terminal lappet is absent, a single 
vagina is present, and the vitellaria extend into 
the haptor; but in Echinoplema the vagina opens 
laterally, while in this species it is median-dorsal 
and situated at the level of intestinal bifurcation. 
Thus the characters of this species which pre- 
vent its inclusion under any of the known genera 
of the subfamily are: (1) the presence of a 
wide median vitelline duct, (2) the compara- 
tively large size of vitelline follicles, (3) the 
position of the testes in a limited space between 
ovary and haptor, the number of testes also be- 
ing limited, and (4) the position of the single 
median vagina at the level of intestinal bifurca- 
tion. In view of these combinations of unique 
characters the new genus Dussumericola has 
been created to accommodate this new species, 
with Dussumericola dussumeria as the type 
species. 
Both the generic and the specific name refer 
to the host. 
Keralina n. gen. 
GENERIC DIAGNOSIS: Choricotylinae, with a 
flowerlike circular haptor, with a complete cir- 
clet of eight clamps borne on short pedun- 
cles; clamps choricotylid but slightly more 
advanced in structure, capsule lip glandular; 
terminal lappet and anchors absent; oral pouches 
fibrous with muscular rim and a median tri- 
angular portion; pharynx with two rows of 
'teeth,’ with glandular and muscular parts; in- 
testinal crura confluent posteriorly and with a 
median vesicular extension into the haptor; 
testes postovarian, penis and cirrus absent, male 
genital pore situated at the level of intestinal 
bifurcation and armed with eight converging 
hooks; vitelline follicles large; vitelline ampulla 
and genito-intestinal canal present; vagina me- 
dian dorsal, unarmed, and situated in the angle 
of intestinal bifurcation; egg spindle-shaped and 
operculate with a filament at each pole. Parasitic 
on the gills of marine fishes. 
GENOTYPE: Keralina opisthopterus n. sp. 
Keralina opisthopterus n. sp. 
Figs. 17-23 
Body broad and more or less oval, with an 
anterior short neck and a posterior flowerlike, 
horizontally expanded circular haptor (Fig. 17). 
Total length 1.15 mm-3.36 mm, and maximum 
width across middle of body 0.63-1.45 mm; 
type specimen 1.74 mm long and 0.84 mm 
broad. 
Mouth subterminal, ventral transverse, and 
bordered by a thick muscular ridge; oral pouches 
more or less rectangular 63 X 63 /a— 126 X 84 /a, 
cuplike, and fibrous, with a triangular muscular 
or glandular structure projecting from the base 
of the concavity (Fig. 18). The inner edges of 
the two oral pouches are parallel and placed close 
to each other along the median line; the pos- 
terior rim is broad and ridgelike with short 
