142 NEMATHELMINTHES chap. 



the caecum of horses ; 0. megatyphlon Kud., in iguanas ; several 

 species inhabit the rectum of insects, such as 0. blattae, 0. diesingi, 

 0. blatticola, found in the cockroach ; 0. sipirotlieca, and 0. 

 hydrophili in the water beetle Hydrophilus} 



The genus Nematoxys has the most complex arrangement of 

 muscles of any Meromyarian, and forms a transition to the 

 Polymyarian type. The whole body of both sexes is covered 

 with numerous irregularly scattered papillae. The members of 

 this genus have hitherto been found in snakes, Amphibia, and 

 eels ; there are but few species. 



Oxysoma is another small genus with but three species, found 

 in the intestines of opossums, frogs, and turtles respectively. 



II. Family Strongylidae. 



Mouth surrounded by papillae ; an armature of teeth or spines 

 often present. The chitinous lining of the intestine projects into 

 the interior as ridges. No oesophageal bulb. The male orifice at 

 the posterior end of the body is surrounded by a bell-shaped bursa. 



Genera : Eustrongylus, Strongylus, Dochmius, Sclerostomum, 

 Cucullanus, Syngamus, Pseudalius, Ollulanus, and others. 



The genus Eustrongylus includes two species, E. gigas Eud. 

 and E. tubifex Nitsch. The former attains in the female the 

 gigantic length of 860 mm., with a breadth of 7 mm. and a 

 weight of over 40 grs. 2 The male is a quarter to a third as long 

 as the female. This parasite inhabits the kidney capsules of carni- 

 vorous animals, especially of those that eat fish, such as dogs, 

 seals, etc., and has occasionally been found in man, the horse, 

 and the deer. It frequently destroys the substance of the 

 kidney. The worms are red in colour. The eggs die when 

 exposed to desiccation for a few days, but have been kept alive for 

 fifteen months in water ; it is believed by Schneider and Leuckart 

 that they are eaten by fish, and that the larvae form the Filaria 

 cystica found in the peritoneal membrane of the fishes Gcdaxias 

 scriba and Symbranchus laticaudatus, and that they pass into 

 their final host, where they become sexually mature, by the latter 

 eating raw fish. E. tubifex is found in aquatic birds, e.g. ducks, 

 grebes, and divers, etc. 



1 Arch. Zool. exper. 1 ser. torn. vii. 1878, p. 283. 



2 Balbiani, Anat. Physiol. 7th year, 1870-71, p. 180. 



