438 THE ANIMAL PARASITES OF MAN 



in the human case the symptoms were mistaken for those of 

 ancylostomiasis. 



Life-history. Rhabditic embryos easily hatch in water, then 

 moult several times, becoming eventually " nlariform " larvae enclosed 

 in the moulted skin. These crawl up blades of grass and are 

 swallowed by sheep, etc. 



Genus. Nematodirus, Ransom, 1907, emend. Railliet, 1912. 



Head over 50^ in diameter. Cuticle may be slightly inflated and 

 often transversely striated. Cuticle with eighteen distinct longi- 

 tudinal ridges. Cervical papillae absent (?). Posterior lobe of bursa 

 reduced to short lobules each with a dorsal ray. Antero-anterior 

 + latero-anterior (= anterior double) rays close together, parallel ; 

 antero-external ray diverges widely from antero- and postero- median, 

 which are close together and parallel. Postero-external ray slender. 

 Spicules more than 0*5 mm. long, at most one-twelfth of body, united 

 by a membrane' throughout their length or only distally. Guber- 

 naculum absent. Vulva behind middle of body. Eggs ellipsoidal, 

 shell rather thick. 



Habitat. Duodenum of ruminants. 



Sub-genus. Mecistocirrus, Railliet, 1912. 



Head slightly inflated, with transverse striations. Skin with 

 eighteen longitudinal ridges, but little apparent ; cervical papillae 

 distinct. Bursa bilobed ; median ray double (= postero-median -f 

 antero-median) ; very large antero-external at the edge, close to the 

 anterior. Spicules very long, slender, one-sixth length of body 

 (3*5 mm.) ; tail pointed. Vulva immediately in front of anus. 



Habitat. Stomach of ruminants. 



Mecistocirrus fordi, Daniels, 1908. 



Syn. : Strongylus fordi, Daniels, 1908; Strongylus gibsoni, Stephens, 1909; 

 Nematodirus fordi, Leiper, 1911. 



Male 21 mm. long by 0-4 mm. thick. Cervical papillae 0-45 mm. 

 behind the head. Spicules about 7 mm. long, i.e., one-third of the 

 body length. At the level of the postero-external rays of the bursa, 

 the bursa has a projecting lobule. 



Female 25 mm. long. Anus 0-2 mm., vulva 0-5 mm. from the tip 

 of tail. Eggs 100 /A by 53/4. 



Sub-family. Ancylostominae, Railliet, 1909. 



Strongylidce with buccal capsule, well developed. Uteri divergent. 

 Parasitic in the alimentary canal, exceptionally in the respiratory 

 system. 



