C. L. Boulenger 
4 00 
oo 
TRIODON TOPHOR US. 
T. serratus 
T. intermedins 
T. tenuicollis 
T. brevicauda 
T. minor 
Length of female 
25 mm. 
16-5-18-7 mm. 
16-19-5 mm. 
16-17 mm. 
14 mm. 
Length of male 
18 mm. 
14-5-15-5 mm. 
13-5-19 mm. 
13-5-14 mm. 
13 mm. 
Mouth collar ... 
Elements of leaf- 
Slightly 
depressed 
at margin 
Circular in 
profile 
Depressed at 
margin 
Erect 
Depressed 
at margin 
crown 
Mouth capsule: 
52-55 
48 
40-44 
60 
44-49 
Height 
0-12 mm. 
0-1-0-13 mm. 
0-07-0-09 mm. 
0-16-0-21 mm. 
0-19 mm. 
Breadth ... 
Capsule teeth: 
0-18 mm. 
0-15-0-18 mm. 
0-11-0-14 mm. 
0-2-0-25 mm. 
0-19 mm. 
margins ... 
Vulva from post. 
Denticulated 
Denticulated 
Denticulated 
Not 
denticulated 
Not 
denticulated 
end ... 
Dorsal lobe of 
More than 
2 mm. 
1-45-1-7 mm. 
0-46-0-56 mm. 
About 0-3 mm. 
About 0-7 mm. 
bursa 
Dermal collar of 
Short 
Short 
Short, sharply 
marked off 
from lateral 
lobes 
Long 
I.ong 
genital cone 
Covers anterior 
Covers anterior 
Completely 
Completely 
Almost 
surface 
surface 
surrounds cone 
surrounds cone 
completely 
surrounds cone 
Spicules 
Comparatively 
thick 
Comparatively 
thick 
Slender 
Slender 
Slender 
,, Length 
4 mm. 
3-5 mm. 
1-25 mm. 
1-75 mm. 
1-8 mm. 
Genus Oesophagodontus Railliet and Henry. 
Oesophagodontus robustus Giles. 
Sclerostomum robustum Giles 1892. 
Oesophagodontus robustus Railliet and Henry 1902. 
This species was described under the name Sclerostomum robustum by 
Giles (1892), who observed a large number of specimens in horses and 
mules in India, they occurred in the colon and caecum in company 
with other worms and were, at least partly, responsible for the severe 
symptoms of sclerostomiasis exhibited by their hosts. 
Although the species has not been rediscovered since that date, it 
has figured frequently in helminthological literature. Giles’ description 
was published before the old-established genus Sclerostomum was split 
up by Looss (1900) and, although on most points accurate, for this 
reason remained incomplete as regards a number of characters now 
recognised as of systematic importance, the result being a considerable 
