CHAPTER II. 
ENTOZOA. 
The internal parasites, or entozoa, are placed under 
the branch Vermes. 
Vermes (vermis—a worm) is divided into three 
classes, viz.: Annelida, Nemathelmintha, and Plat- 
helmintha. 
Annelida (annulus—a ring) includes the order 
Discophori. This order includes the family Gnath- 
obdellidae. This family includes the genus Haemo- 
pis, which infests the pharynx and mouth. 
Nemathelmintha (nema—thread; helminth— 
worm) is divided into two orders, viz.: Nematoda 
and Acanthocephala. 
Nematoda (thread-like) is divided into five fam- 
ilies, viz.: Filaridae, Ascaridae, Oxyuridae, Strongy- 
lidae and Trichotrachelidae. 
Filaridae (filum—a thread) include the genera 
Spiroptera, Simondsia, and Filaria. They are 
thread-like worms infesting various parts of the body. 
Ascaridae (askarizo—to move briskly) include 
the genus Ascaris, which infests the small intestines. 
Oxyuridae (oxyo—pointed; oura—tail) include 
the genus Oxyuris, which infests the posterior bowel. 
Strongylidae (strongylos—cylindrical) include 
the genera Strongylus, Sclerostoma, Stephanurus, 
Syngamus, Oesophagostoma and Uncinaria, which 
infest the various parts of the body. 
Trichotrachelidae (trix—hair) include the genera 
Trichocephalus and Trichina, which infest the in- 
testinal tract. 
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