656 



NEMA THELMINTHES 



Remarks.^ — Toxascaris cams is the common Ascaris of dogs, which 

 used to be called A . canis, but recently Leiper, when examining a 

 number of specimens of A. lumbricoides in Egypt, found among them 

 several smaller and apparently younger forms. On examining these 

 he found that they had winged expansions on either side of the head, 

 which indicated that they were not A. lumbricoides. On further 

 examination they proved to be the same species as that found in 

 dogs, but differed from that found in cats. Up to that time A . canis 

 in the dog and A . mystax in the cat were supposed to be identical. 

 Finally, on careful anatomical examination, it was found that the 

 two not merely differed considerably from one another, but also 

 from A^. lumbricoides. He therefore formed two new genera— 

 Toxascaris and Belascaris. So far, Toxascaris has only been 

 recorded once in man. 



Morphology.— Body white or reddish, head curved dorsally, with 

 two membranous lateral expanisons, broader behind than in front. 

 Male 5 to lo centimetres in length, with curved tail, possessing two 

 small lateral membranous wings and twenty-six papillae. Female 

 9 to 12 centimetres in length, with an obtuse tail. Eggs 75 to 80 ^ 

 in diameter. 



Life-,History. — Development is similar to A. lumbricoides. 



Pathogenicity. — -It often causes intestinal and nerve symptoms in 

 dogs. Post mortem the mucosa of the intestine is tumefied and 

 catarrhal. 



Belascaris Leiper, 1907. 



Definition, — ^Ascaridse with the anterior end of the body bent 

 ventrally, cuticle coarsely striated, oesophagus with a distinct 

 bulbous portion. Male with a probular tail— i.^., like a closed fist, 

 with forefinger semi-extended. Immediately behind the anus there 

 is a protuberance, with a pair of papillae. On the tail there are 

 two ventral and two lateral pairs of papillae, the tips of which 

 support a slight expansion of the cuticle. The testis is situate in 

 the anterior half of the body. The vesicula seminalis is remarkably 

 long, and there is a short ejaculatory duct. Female with vulva 

 situated in the anterior part of the body. Egg with a honey- 

 combed shell. 



Type. — Belascaris cati Schrank, 1788. 



Belascaris cati Schrank, 1788. 



Synonyms. — Fusaria mystax Zeder, 1800; Ascaris alata Belling- 

 ham, 1839. 



This Ascaris is common in cats, and has been recorded nine times 

 in man. 



Morphology. — Head curved ventrally, with two membranous 

 lateral expansions. Male 4 to 6 centimetres in length; female 

 4 to 10 centimetres in length. 



Life-History. — Similar to A. Imnbricoides. 



Pathogenicity, — It rarely causes any symptoms. 



