1910.] ON ENTOZOA OF THE HIPPOPOTAMUS. 233 



6. The Entozoa of the Hippopotamus. By Robert T. Leiper, 

 M.B., F.Z.S., Helminthologist to the London School ot* 

 Tropical Medicine. 



[Received February 1, 1910.] 



(Text-figures 26-35.) 



The parasites described in this paper were, with two exceptions, 

 collected by me on the occasion of a visit to Uganda during the 

 summer of 1907, as a member of the Egyptian Government 

 Survey. 



During a month's stay near the Murchison Falls on the Victoria 

 Nile I dissected four Hippopotami for the purpose of ascertaining 

 to what extent they harboured parasitic worms. 



In every case worms were present in large numbers in the 

 stomach, intestines, liver and subcutaneous tissues, comprising no 

 less than nine species, of which three were round worms and six 

 flat worms — no tapeworms occurred. 



Shortly after my return to England I received from Dr. Sells, 

 of the Uganda Medical Staff, a collection of parasites from various 

 animals. Among these were two new species from the Hippo- 

 potamus that did not occur in my own series, but which for the 

 sake of completeness are recorded here. 



NEMATODA. 

 Family Trichostrongylid^e. 

 Genus Nematodirus. 

 1. Nematodirus hopkeni, sp. n. (Text-fig. 26, p. 234.) 



The habitat of this species is somewhat uncertain, as the few 

 specimens representing it were found upon the peritoneal surface 

 of the intestine and stomach after these had been opened. There 

 seems little doubt that they had escaperl from the stomach. The 

 males are easily distinguished from the females by the presence of 

 a bursa at their posterior ends and by their smaller size. The 

 males measure 12 mm. and the females 18 mm. in length. 

 The skin is transversely striated, and the striae at the level of the 

 junction of oesophagus with intestine are 0"003 mm. apart. 



The mouth is unarmed, but is surrounded by three tiny 

 lips. 



The oesophagus is simple and gradually increases in diameter 

 from its anterior to posterior end. At 0*3 mm. from the mouth 

 it is crossed by the nerve ring, and at the same level the excretory 

 pore opens on the ventral surface of the body. In the male, the 

 bursa surrounding the posterior extremity consists of two long 

 lateral flaps supported by six rays. The third or posterior mem- 

 brane with its supporting posterior ray is entirely absent. 



