ORDER INTESTINA. 459 
internal organs of generation consist in very long vessels, con- 
taining the semen, or the eggs, and having their issue at dif- 
ferent points according to the genera. 
FILARIA, L., 
Have the body elongated and slender, in the form of a thread, 
pierced in front with a round mouth. Externally they very 
much resemble the gordius. They are principally found in 
the cavities of animals, which have no external issue in the 
cellular substance, and even in the thickness of the muscles, 
and the parenchyma of the viscera. They are sometimes in 
parcels, and in innumerable quantities, enveloped in sorts of 
capsules. ‘They are even found in insects, and in their larve, 
and in the visceral cavity of several of the mollusca. 
The most celebrated species of this genus is, 
Filaria Medinensis, Gm. Encyc. xxix. 3. (Vulg. Guinea- 
Worm.) Very common in warm climates, where it insinuates 
itself under the human skin, principally in the legs, and is 
sometimes developed there, to the length of ten feet and more, 
if we may credit the accounts of some writers. It can subsist 
there for several years, without causing any very lively sensa- 
tions ; but it also sometimes produces very dreadful pains and 
convulsions, according to the parts which it attacks. When 
it shows itself externally, it is seized, and drawn out very 
slowly, for fear of breaking it. It is as thick as the quill of a 
pigeon’s feather. Its distinctive character is to have the end 
of the tail pointed and hooked. 
TRICHOCEPHALUS, 
Have the body round, thicker behind, and as slender as a 
thread in front. This slender part is terminated by a round 
mouth. 
The most known is, 
Trich. dispar. Rud. Goetz. vi. 1—5. Encyc. xxxiii. 1—4. 
