W. Nicoll 
123 
Habitat : Gall-bladder and liver of birds. 
Type : P. biliosum Nicoll from the gall-bladder of stone-curlew 
(Burhinus grallarius), North Queensland. Type specimen T. 81. 
A.I.T.M. collection. 
Family Clinostomidae. 
Sub-Family Clinostominae. 
Clinostomum hornum n. sp. 
(Plate VII, fig. 12.) 
A couple of specimens, only one of which was mature, were obtained 
from the trachea and oesophagus of a Nankeen night heron ( Nyctidorax 
caledonicus). Half a dozen immature specimens of what appears to be 
the same species were found in the oesophagus of a bittern ( Botaunus 
poeciloptilus). They present a very close resemblance to C. marginatum 
(Rud.) and C. complanatum (Rud.) but differ from the former in possess¬ 
ing less voluminous yolk glands, much smaller eggs, and in having the 
genital aperture distinctly lateral on the right side. From C. com¬ 
planatum they differ in having the ventral sucker nearer the middle of 
the body. In both these species the oral sucker is decidedly smaller 
than in the present species. 
The length of the mature specimen is 4'6 mm. and the greatest 
breadth, which occurs at the level of the ventral sucker, is 1'45 mm. 
The breadth, however, is fairly uniform. The posterior end of the body 
is gently rounded ; the anterior end is slightly truncated. The oral 
field is well developed and the oral sucker measures 0‘4 mm. in diameter. 
The ventral sucker lies 1'2 mm. from the anterior end and has a diameter 
of 0‘7 mm. 
The walls of the intestinal diverticixla are thrown into well-marked 
folds both on their inner and outer surfaces but there are no side 
branches. 
The anterior testis is separated from the ventral sucker by a space 
of 0‘7 mm. It is irregularly triangular in outline with the apex directed 
backwards and towards the middle line. Its greatest diameter (obliqixe) 
is 0'65 mm. A short distance behind it lies the second testis which is 
somewhat heart-shaped, the apex pointing backwards. It measures 
0'56 x 0'63 mm. 
Between the two testes on the right side, lies the small ovary. 
The yolk glands extend from just behind the ventral sucker to a short 
9—2 
