AN ACCOUNT OF SOME HELMINTHES COLLECTED IN THE SUDAN 
195 
T K E M A T O D A 
Family, I’aeamphistomid*. Suh-fam., rarainphistomince 
Genus, Gastrothylax, Poirier 
Gastrolhylax icenyoni, n. sp. 
Mrs. Gray’s Waterbuck. Cobus ilaria. Stomach. Tauiikia, White Nile. 
This parasite was obtained in large numbers from the stomach of a waterlnick. The 
fixation was very good, and perfect serial sections were obtained illustrating all the various 
structural details. Like its congeners, it has a strikingly red coloration which remains after 
preservation in alcohol or formalin. This appearance in itself distinguishes the species of 
Gastrothylax at once from other Paramphistomes, and the diagnosis may most rapidly be 
confirmed by observation of a pore upon the ventral surface a little behind the anterior 
extremity and additional to the two terminal pores met with in the Paramphistomidce. This 
pore gives exit to a large spacious pouch that occupies a considerable part of the interior of 
the Gastrothylax body, extending backwards to the anterior limit of the musculature of the 
posterior sucker. A rough transverse cut of the body reveals the large cavity to the naked 
eye, and clinches the diagnosis without microscopical study. Although this ventral pouch 
is absolutely constant, and is indeed not only the chief characteristic of the genus but a 
feature also in the variations of its shape and extension, in the differentiation of species, 
yet we still know nothing of its function. It ends blindly, receives only the genital pore 
in its anterior portion, and is found never to contain undigested stomach contents of its 
host, or indeed any solid substances (Fig. 47). 
v p.=s ventral pouch. p.s. ssposterior eucker. 
ex.V. =excretory vesicle. ov. =:ovary. 
sb.gl. =shell f^Iond. ot. = uterus. 
The nine species that have been allocated to this genus have been recently grouped 
by Fischbder according to the configuration of the buccal pouch in section across the 
body of the animal. 
i last rot hy lax, 
Poirier 
