Round Worms {Nematoids) of Solipeds. 271 



teeth, but it has in addition four large prominent papilla from 

 which the specific name is derived. It is further smaller than the 

 equinum, the males being 8 to 15 mm. long, and ^& females 10 

 to 24 mm. The m.ale has two delicate spicula of equal size and 

 a shell-like clasping apparatus supported by rays. The female 

 has the tail rounded but with a delicate sharp point, unlike the 

 equinum. 



Ovum an elongated ellipsis, twice as long as thick. 



Habitat. In the caecum and colon of solipeds often in great 

 numbers, and in company with the sclerostoma equinum. It is 

 distinguished from the latter by its smaller size, by the 4 large 

 papillae around the mouth, by the sharp spike on the otherwise 

 rounded tail of the female, by the length of the elliptical ovum, 

 and by the longer tail and more sluggish movements of the 

 embryo. The latter are hatched out in the intestine and may at 

 once bore into the mucosa and encyst themselves, or escaping 

 with the faeces they may reenter in the water and food and find a 

 temporary home in the cysts in question. They are not known 

 to wander into the bloodvessels like the sclerostoma equinum. 

 The latter in the sexually immature condition live in the blood- 

 vessels, while the former establish themselves in cysts in the 

 mucous membrane, and in pill-like masses of solid ingesta in which 

 they excavate for themselves a temporary home. The latter are 

 the netnatoideum equi caballi (Diesing), and trickonema arcuata 

 (Cobbold), which the latter finally recognized to be the agamous 

 larvae of the sclerostoma tetracanthum . These larval asexual par- 

 asites must migrate into the bowels to attain sexual development 

 and propagate their kind. 



Pathogenesis. This is by no means so dangerous as the 

 sclerostoma equinum since it leads to no blocking of the mesen- 

 teric vessels, yet when present in large numbers the countless 

 wounds which it makes in the mucosa, and the irritation caused 

 by the encysted larvae, often produce congestion, indigestion, and 

 enteritis. Apart from this, anaemia and chronic catarrh of the 

 large intestine are common results of their ravages. 



Symptoms. Beside the general manifestations of intestinal 

 parasitism, there are the local symptoms of anal pruritus, the 

 broken, twisted condition of the hairs at the root of the tail, the 

 dried fur around the anus, and the passage of the specific worm 

 with the faeces. 



