99 
Charles L. Boulenger 
4. Cylicostomum minutum Yorke and Macfie, 1918. 
5. „ zebrae sp. n. 
6. „ Montgomeryi sp. n. 
7. Triodontophorus serratus (Looss, 1900). 
8. Craterostomum tenuicauda gen. et sp. nn. 
The species numbered 1, 4 and 7 are also parasites of the domestic equines. 
Family Strongylidae. 
Subfamily Cylicostominae Railliet, 1914 . 
Genus Cylindropharynx Leiper, 1911. 
Cylindropharynx brevicauda Leiper, 1911. 
The type species of the genus is more abundantly represented in Mr Mont¬ 
gomery s collection than 0. longicoudci. Leiper has given a fairly complete 
account of the species, a few characters are, however, omitted from his 
description and I take this opportunity of adding to our knowledge of certain 
important structures, e.g. the oral leaf-crowns and the external genitalia in 
the male sex. 
The specimens before me measure: Females, 5*6-8 mm., males, 5-7*3 mm. 
in length; maximum breadth of the body, about 0*45 mm. 
The head (measured at the anterior extremity of the mouth-capsule) 
has a diameter of 0*12—0*15 mm. The mouth is circular and surrounded by a 
mouth-collar which appears almost semicircular in a lateral view (Text-fig. 1). 
The lateral papillae are not prominent, they are situated in a slight depres¬ 
sion of the oral margin and have trifurcated extremities, recalling the similar 
structures in Oesophagodontus robustus (cf. Boulenger, 1916). The submedian 
papillae are conspicuous, each consists of a leaf-shaped appendage carried on 
a cylindrical base (Text-fig. 1 , a). 
The anterior leaf-crown consists of six triangular elements unequal in 
size and arranged in a very characteristic manner; four occupy a submedian 
position and are of equal, relatively small size, the two remaining leaves are 
: much broader and situated laterally, each is usually notched at the apex and 
i longitudinally grooved, suggesting an origin by fusion of at least two elements. 
' Owing to the lack of radial symmetry of these organs, the head presents very 
i different appearances when viewed 1 laterally or from the dorsal or ventral 
sides (Text-fig. 1 , a and b). 
The posterior leaf-crown consists of a circle of twelve broad, elongated 
leaves arising from the anterior margin of the mouth-capsule, the leaves are 
j extremely thick, in profile (Text-fig. 1 , a) they might be taken for anteriorly 
directed branches of the oral capsule. 
The very characteristic mouth-capsule measures 03-0*4 mm. in length 
with a maximum diameter of 0*09-0*12 mm., its internal surface is lined with 
a transparent chitinous layer, as in many species of Cylicostomum. 
