362 
The Lung Parasites of Cattle and Sheep, 
Although helminthologists are more or less well acquainted 
with all these five parasites in their full-grown state, not one of 
the worms has been followed throughout the various stages of 
its life. In other words, [the present state of our knowledge 
of the natural history of each species is incomplete. As an aid 
to further investigation, it is now proposed to supply a brief 
diagnosis or statement of the characters that distinguish each of 
the above-named species, followed by a detailed account of the 
origin and development of the common lung-worm of cattle. 
The supposition that earth-worms are intermediately concerned 
in the production of the cattle lung-worm, has arisen solely from 
the circumstance that the writer, some time ago, conducted a 
set of original investigations, the results of which seemed to 
warrant such a conclusion. Before the truth of this position, 
however, can be universally accepted, it is necessary to publish 
figures and descriptions of the young worms, for the purposes of 
comparison and verification. 
1. Strongylus micrurus (Mehlis). — This parasite is easily 
recognised by the relatively small size of the hood or bursa 
attached to the tail of the male, and also by the pattern of the 
rays, which are disconnected at their points of origin (Fig. 1). 
The male worm attains the length of nearly an inch and a-half ; 
the somewhat stouter female reaching two inches and a-half. 
This parasite not only infests cattle, especially calves, but it 
also attacks horses and the ass. It has been obtained from the 
fallow-deer, and is probably the chief cause of lung-disease in 
the deer-tribe generally, although it is apt to be confounded 
with the next species. 
2. Strongylus jilaria (Rudolphi). — This worm possesses a 
longer and larger hood, which is cleft or incomplete at the 
upper or front part, whilst the various rays are united at their 
common base. The male worm is commonly about an inch 
long ; but, according to Gurlt, it sometimes almost equals the 
length of the female, the latter extending to three and a-half 
inches. This species infests sheep, especially lambs. It also 
attacks the goat, roe, and fallow, as well as the deer-tribe in 
general. Even camels suffer from its presence. 
3. Strongylus paradoxus (Mehlis). — This worm is distin- 
guished by the remarkably delicate and usually crumpled-up 
hood. Until comparatively recently, no one had been able 
to detect the presence of rays within the membrane of the 
hood. These rays are altogether peculiar in shape, the hood 
itself being four-lobed (O. von Linstow). This species is a 
common cause of lung-disease in swine ; but, according to Alois 
Koch, it infests sheep and lambs. The male is three-quarters 
of an inch in length, and the female an inch and a half. It 
