662 



NEMA THELMINTHES 



Family 12: Metastrongylid^ Leiper, 1912. 



Nematoda with simple mouth, very small cavity, and not enlarged 

 to form a buccal capsule, and a bursa in the male with true but 

 stunted rays. Two spicules. 



This family includes a number of genera, parasitic in the lungs of 

 domesticated animals. 



Metastrongylinse Leiper, 1908, 



MetastrongylusMolin, 1861. 



Metastrongylidae with mouth surrounded by six small papillae. Male with 

 a bursa copulatrix and two spicules. Female with two ovaries and a tapering 

 posterior end ; vulva situate in the hinder half of the body. Embryos without 

 teeth, and with slightly developed oesophageal bulb. 



Metastrongylus apri Gmelin, 1789. 



Synonyms. — Gordius pulmonalis aph Ebel, 1777; Ascaris apri Gmelin, 1789; 

 Strongylus suis Rudolphi, 1809; S. paradoxus Mehlis, 1831 ; S. elongatus Du- 

 jardin, 1845; S. longevaginatus Diesing, 1851. 



Metastrongylus apri is not uncommonly found in the bronchial tubes of pigs 

 in Germany (60 per cent. Berlin, 15 to 52 per cent. Leipzig); occasionally it 

 infects other animals, including man. Filaria trachealis Rainey, 1855, found 

 by Rainey and by Bristowe, may be infection of man with this parasite. 

 Diesing recognized the worm in the lung of a boy aged six in Klausenberg in 

 1845. It is said to also occur in the intestine, but this is looked upon as 

 accidental, as its usual habitat is the lung, where it may cause pneumonia and 

 bronchitis. 



Morphology. — Body relatively short; colour, white or brown; mouth with 

 six lips, of which the two lateral are the largest, Male: 12 to 25 millimetres 

 in length, with bilobed bursa with five ribs in each lobe, and thin spicules 

 about 4 millimetres in length. Female : 20 to 40 millimetres in length, with a 

 curved posterior end, close in front of which is the anus, while the vulva opens 

 on a papilla just in front of this. Eggs elliptical, 50 to 100 ^ by 39 to 72 /x; 

 when oviposited, they already contain an embryo. 



Life-History. — Only the embryonic and larval development appear to have 

 been studied. From analogy with Ankylostoma a skin infection would be 

 presumed nowadays, and, further, the fact that the worms have been noted 

 in the alimentary canal bears quite a different significance from what it did 

 years ago, as it may be natural for the worms at times to travel from the lungs 

 to the bowel like the Ankylostoma. It is interesting to note that Leuckart 

 failed to infect sheep by feeding them with bronchial mucus full of embryos. 



Pathogenicity. — This subject has recently been studied hy Santiocchi, and 

 consists essentially of bronchitis, broncho-pneumonia, and pneumonia. 



Family 13: Trichostrongylid^ Leiper, 1912. 



Nematoda with filiform bodies; cuticle markedly striated trans- 

 versely or longitudinally; mouth without buccal capsule or tooth 

 armature; bursa large, with well-developed rays; genital pore in 

 posterior half of body; ovijectors present; oviparous. Intestinal 

 parasites. 



Nematodirus Ransom, 1907. 

 Trichostrongylidse with bursa provided with double ventral median ribs, 

 two dorsal ribs, spicules long and filiform, without accessory piece. Head 

 50 microns in diameter; cuticle with eighteen distinct longitudinal ridges. 

 Cervical papillae absent. 



