GNATHOSTOMID.E 



169 



must never be considered to be completely relieved until 

 the stools have been found to be persistently free from 

 the eggs. 



Ascaris cams or mystax is a common parasite of cats 

 and dogs, and may be found in man. It is a much 

 smaller worm than A. lumbricoides ; the males are 40 mm. 

 to 60 mm. in length, and the females one-quarter larger. 



On each side of the anterior extremity the cuticle is 

 expanded into broad longitudinal ridges the alar append- 

 ages. Those infesting dogs and cats are distinct species, 

 as the shape of the alar appendage varies. Leiper con- 

 siders that the differences are sufficiently great to consider 

 them as belonging to different genera. That of the cat 

 he names Belascaris mystax, whilst that of the dog, in 

 which the alae are longer and divided by a depression 

 into two lobes, he calls Toxascaris limbata. Both forms 

 have been observed in man. 



FIG. 67. Gnathostoma siamense. To the left, the entire worm, enlarged ; 

 to the right, the head seen from above, much enlarged. (After Levinsen.) 



GNATHOSTOMID^E. 



Gnathostomidce. Most of the members of this group 

 are intestinal parasites. They are short worms with a 



