ENTOZOA. 349 
perceive vestiges of nerves so extremely obscure, that many 
naturalists have doubted their existence(1). 
When those characters are found united in an animal with 
a form similar to that of this class, we place it here, although 
it may not inhabit the interior of another species. 
The injury caused by worms to animals, in which they be- 
come excessively multiplied, is well known. The most efli- 
cacious agent for destroying those of the alimentary canal 
seems to be animal oil mixed with spirits of turpentine(2). 
We will divide the Entozoa into two orders, which are 
perhaps sufliciently different in organization to form two class- 
es, if we had the observations requisite to determine their li- 
mits. These orders are the 
EntTozoa NEMATOIDEA, Rud. 
Which have an intestinal canal floating in a distinct abdo- 
minal cavity, a mouth and anus; and the 
EnTozoA PARENCHYMATA(3), 
Where the parenchyma of the body contains obscurely ter- 
minated viscera, most commonly resembling vascular ramifi- 
cations, and sometimes not visible. 
(1) For the anatomy of these Worms, besides the Entozoa of Rudolphi, see the 
Mem. of M. Otto, Soc. Nat. Berl., 1816, and the work of M. J. Cloquet. 
(2) See Chabert, Traité des Maladies Vermineuses, and Rudolphi, I, p. 493. 
(3) They comprise the four last orders of Rudolphi. 
