206 DR. M. KHALIL ON THE NEMATODE 



Thei'e is some confusion regarding the correct zoological 

 terminology of the species of elephants. For this reason the 

 term.s African and Indian are used thioughout this work. 



NEMATHELMINTHES. 



Class NEMATODA. 



Super-family Rhabdiasoidea Kailliet, 1916. 



Family A T R A T i D .E Travassos, 1919. 



This family name was given by Travassos to include the 

 following genera : — Atractis, Ozolaimtos, liodonia, Labiduris, 

 Crossocephcdus, Macracis, Cobboldina, and Cyrtosoormm, to which 

 I add the genus Leiperenia. 



Travassos' diagnosis of the family runs as follows : — CEsophagus 

 with an anterior and a posterior bulb ; viviparous, the female 

 genital system is generally single ; vulva is placed posteriorly or 

 in common with the anus ; parasites of vertebrates. 



Genus Leiperenia Khalil, 1922. 



Small nematodes just visible to the naked eye. The males are 

 slightly smaller than the females. Mouth is surrounded by moi'e 

 than six lips. CEsophagus is divided into an anterior, short, and 

 strongly muscular portion, to which the name pharynx is given. 

 The posterior portion of the a\sophagus is about three times as 

 long as the pharynx. The anterior end of the body is provided 

 with a cuticular membranous expansion on either side. There 

 is a large excretory' vesicle. The excretoi-y pore is raised on a 

 papilla which is striated radially. 



Male : The caudal extremity of the male is curved. There are 

 two unequal spicules and an accessory piece. There are four 

 papillse on the tail. 



Female : Viviparous, and the embryos reach an advanced 

 stage of development in uiero. The vulva is placed in the 

 posterior part of the body, separate, and a short distance in 

 fi^ont of the anus. 



Type-species, Leiperenia leiperi (from the African elephant). 



Leiperenia leiperi Khalil, 1922. (Text-figs. 1-4.) 



Material. — The material consists of two males and three 

 females, taken from Prof. Leiper's collection of Elephant 

 nematode parasites. 



Shape of body. — These nematodes are very small and just 

 visible to the naked eye. The males are 3-8 mm. long. The 

 females are slightly longer, being 3*9 mm. in length. The 

 maximum diameter of the body is about the middle: it is "2 mm. 

 in the male and '21 mm. in the female. The body narrows 

 slightly as it is traced towards the head end, which is truncated 



