PARASITIC NEMATODES FROM TROPICAL AFRICA. 551 



Family S x R o N G Y L id /E. 



Subfamily Cylicosxomin.e. 



Genus Cylindropharynx, gen. n. 



Species brevicauda, sp. n. (Type sp.) 



Host : Zebra. Locality : British East Afiica. 



The Zebra is the subject of a considerable numlier of parasites 

 that occur normally in the Horse, but in addition it appears to 

 have found a few peculiar to itself. While examining a number 

 of Oylicostominas cleared in glycerine, I noticed a number of 

 specimens that appeai-ed to have an abnormally deep buccal 

 capsule. The shape of this capsule struck me at once as of generic 

 value, and on further search I was soon able to distinguish in the 

 material two distinct species showing this special character. 



To the naked eye appeai-auces the species of this genus resemble 

 exactly those of Cylicostomum. The mouth is surrounded by a 

 collar bearing a double corona radiata. In G. brevicauda^ the 

 type species, the buccal capsule is cylindrical, and has a thick 

 chitinous wall measuring 0'4 mm. in depth and 0"1 mm. in 

 transverse diameter. The oesophagus is exceedingly short and 

 fleshy, measuring 0-46 mm, in length and 0"18 mm. in greatest 

 diameter. The nerve-ring surrounds the oesophagus immediately 

 behind its union with the buccal capsule (text-fig. 141, A, p. 552). 

 In the female, the posterior end tapers very quickly from a diameter 

 of 0"25 mm. at the level of the vulva to a pencil-like point. The 

 vulva opens at 0'7 mm., the anus at 0*18 mm. from the extremity 

 (text-fig. 141, C). In the male the bursa shows a characteristic 

 disposition of the i^ays. The posterior ray is split to its base into 

 two portions, and each of these is again split as far into an internal 

 and external ray. The external ray is bifui'cated as it reaches the 

 edge of the bursal membrane (text-fig. 141, D). The genital cone 

 is very large aiid protuberant. The spicules are long and filiform, 

 measuring 1 mm. in length. There is a stout thick uneven accessory 

 piece 0"2 mm. in length (text-fig. 141, B). The edge of the bursal 

 membrane is finely serrated as in the genus TriodontojjJiorus. 



Cylindropharynx longicauda, sp. n. 

 Host : Zebra. Locality : British East Africa, 

 This species closely resembles C. hrevicauda, but the buccal 

 capsule is smaller, measuring only 0"23 x 0-07 mm. The oesophagus 

 is more slender, measuring 0-42 x 0-12 mm. (text-fig. 142, A). 

 In the female the tail is long and pointed. The vulva is situated 

 much farther forward in this species, opening at 1'55 mm., whilst 

 the anus opens 0"32 mm. from the posterior extremity (text- 

 fig. 142, D). In the male the spicules are shorter, 0*7 mm. The 

 accessory piece is less developed and shorter, 0*13 mm. The genital 

 cone is more globular (text-fig, 142, B). The rays differ more par- 

 ticularly in that the external branch of the posterior is umlivided 

 (text-fig. 142, C). (Collected by Dr. J. T. C. Johnson.) 



