362 
T. F. WINCHESTER. 
very readily by the ova, which are usually present in large 
numbers. 
The eggs are ovoid, and measure 92/i and 54M broad. The 
dimensions are variable; sometimes the males are 18 mm. to 
20 mm. long, and the females 20 mm. to 26 mm., and at other 
times it is respectively 26 mm. to 35 mm. and 35 mm. to 55 
mm. 
The worms are found in an agamous or undeveloped 
state in blood vessels (Plate- II.). In this condition they are 
covered by a thin, transparent membrane, which entirely 
covers and closes the still undeveloped worm. It has a tem¬ 
porary mouth and oesophagus, which lead directly into the 
still imperfectly formed mouth. This worm infests the cae¬ 
cum and commencement of the large colon, and, with the as- 
caris megacephala, is the worm most commonly found in the 
equidae. 
The armed sclerostome holds firmly by the buccal arma¬ 
ture to the mucous membrane, which forms at the point of 
adherence a small, dark prominence. They are frequently 
met with in couples, the two individuals forming an almost 
right angle, and adhering so intimately that they may be pre¬ 
served in this condition in alcohol. Notwithstanding their 
sometimes considerable numbers, and the irritation they 
should produce in the mucous membrane, their presence in 
the horse is rarely betrayed by any appreciable symptom. 
They have sometimes been accused of causing death by anae¬ 
mia, diarrhoea, colic, etc. 
It is not only on the internal surface of the large intestines 
that they are met with, for they are found in aneurisms of 
the mesenteric artery, and in the hepatic, renal, spermatic, 
occipital and other arteries; in the muscles, pancreas (Gou- 
baux, Montane) ligaments of the liver, and in submucous 
cysts of the caecum, and sometimes of the duodenum. In'all 
these instances they are in an agamous state, and represent 
one of the phases in the development of the species. 
With regard to the intestinal tumors, their volume varies 
from that of the head of a pin to that of a hazel or small al¬ 
mond-nut, according to the development attained by the 
