ox NEW PARASITIC NEMATODES FFtOM TROPICAL AI-'RTCA. 541) 



25. Some new Parasitic Nematodes from Tropical Africa. 

 By Robert T. Leiper, D.Sc, M.B., F.Z.JS. 



[Received April 4, 1911 : R«ad April 25, 1911.] 



(Text-figures 140-144.) 



In the following paper I give a brief description of a number 

 of new genera that have recently come under my notice in the 

 course of an examination of helminthic material collected by me 

 during a visit to East Africa, Uganda and the Soudan, whilst a 

 member of the Egyptian Government Survey in 1907, and of 

 further material sent to me at the London School of Tropical 

 Medicine by members of the Colonial Medical Service. 



NEMATODA. 



Family A n c y l o s t o m i d vE. 



Genus AcHEiLOSTOMA, gen. n. 



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



Host : a large rodent. Locality : Nigeria. 



A large number of specimens was collected from the ali- 

 mentary canal and preserved in 70 7o alcohol. The males measure 

 17 mm. in length, the females 23 mm. in length. The former 

 are less numerous than the latter. The cuticle shows marked 

 transverse striation in the anterior end of the body. The indi- 

 vidual striee are so deeply cut as to give the edge of the cuticle 

 in this region a serrated appearance. At a distance of 0'8 mm. 

 from the anterior end are two large stout lateral papillae curving 

 backwards and shaped like large thorns (text-fig. 140, A, l.p. p. 550). 

 The anterior end of the body is bent dorsally only very slightly, 

 showing that the oral aperture, which is surrounded by a thick 

 collar, 0*004 mm. deep, is almost but not quite terminal. The 

 mouth capsule shows similar characters to those found in other 

 members of this family. There is a large median ventral tooth 

 and two fan-shaped inner teeth guarding the oesophageal entrance 

 to the buccal capsule dorsally (text-fig. 1 40, D). The buccal capsule 

 has a chitinous wall, and resembles that of Necator rather than that 

 of Ancylostovium. The most striking feature of the genus, how- 

 ever, is the entire absence of teeth or cutting-plates guarding the 

 entraace to the oral aperture. There is no indication either of .a 

 corona radiata ; so that although the buccal cavity of the parasite 

 recalls that of the Ancylostomes in its internal characters, the oral 

 aperture reminds one rather of the Bunostomes. 



The oesophagus measures 0-95 mm. in length and shows no 

 special characters. In the female the genital pore lies almost 

 at the centre of the body. The eggs in the uterus measure 

 0-055 mm. x 0'032 mm. and usually contain a few segments. 



In the male, the posterior end of the body is surrounded by a 

 Proc. Zool. Soc— -1911. No. XXXVI. 36 



