432 
Sclerostomes of the Horse 
The spicules are slender (Text-fig. 6 C), the hooks are more strongly 
recurved than in T. tenuicollis and are further characterised by the 
peculiar hammer-shaped “barbs” at their junctions with the shafts. 
T. brevicauda was found in the colon and caecum on several occasions, 
like T. intermedins it never occurred in large numbers. The species is 
obviously closely allied to T. minor Looss; it can, however, be readily 
distinguished by the shape of the mouth-collar, by the peculiar structure 
of the tail region in the females, and by the characters of the spicules 
in the males. 
Fig. 6. Terminal portions of spicules. A. T. intermedins Sweet. B. T. tenuicollis sp. n. 
C. T. brevicauda sp. n. x 375. 
It will be seen from the diagnoses given above that, apart from size, 
the various species of Triodontophorus are distinguishable by the com¬ 
binations of various well-marked characters, the most important of 
which are: in both sexes, the shape of mouth-collar and the shape and 
size of the oral capsule; in the females, the shape of the “tail” and the 
distance of the vulva from the posterior extremity; in the males, the 
form and size of the dorsal lobe of the bursa and the spicules. The 
more important of the distinctive characters are tabulated on the 
opposite page; in the case of T. serratus and T. minor the various 
measurements have been obtained from Looss’ monograph (1901), 
either from the text or the plates. 
