350 ENTOZOA. 
ORDER I. 
NEMATOIDEA, Rud.(1) 
This order comprises those whose external skin, more or 
less furnished with muscular fibres, and usually striated trans- 
versely, contains an abdominal cavity in which is a distinct 
intestinal canal, extending from the mouth to the anus, and 
where we generally observe distinct organs in each of the 
sexes. The intestine is connected with the neighbouring 
parts, and the general envelope of the bedy by numerous 
threads, considered by some writers as vessels for the con- 
veyance of the nutritious fluid, and by others as trachex, but 
without any proof of the fact. It is impossible to detect any 
true circulation in these animals, but in several there appear 
to be one or two nervous cords arising from a ring which sur- 
rounds the mouth, and extending the whole length of the body 
along the internal surface of the envelope. - 
The intestine is generally straight, and tolerably wide; the 
esophagus is frequently smaller, and in some species we re- 
mark a larger and more vigorous stomach. The internal or- 
gans of generation consist of extremely long vessels, contain- 
ing the semen or the ova, which open at different points, ac- 
cording to the genus. 
Finari, Lin. 
Where the body is elongated, slender, filiform, and perforated at 
the anterior extremity by a round oral aperture. The Filariz in 
their external appearance are very similar to the Gordii. They are 
chiefly found in those cavities of animals which do not open exter- 
(1) This order, with the exception of the two last genera, constitutes the En- 
TOMOZAIRES Aropes Oxyceruanes of M. de Blainville. 
