NEMATODA. 765 



(S. 0. 2.) Trematoda (Flukes). 

 Gen. Distoma. 



Amiiliistoma. 

 CI. II. Nemathelminthes (Eound-worms). 



(N. 0. 1.) Nematoda (Round- worms proper). 

 (Group a.) Polyimjaria. 

 Gen. Ascaris. 



Uustrongijltis. 



Filaria (including Sjpiroptera). 

 (Group h.) Meromyaria. 

 Gen. Oxyuris, 



Strongylus (including Dochmius). 

 (Group c.) Holomyaria. 



Gen. Trichina. 



T'richocephalus. 

 (N". 0. 2.) Acantliocepliala (Thorn-lieaded worms). 

 Gen. Echinorhynchus. 



Sub-Kingdom Arthropoda. 

 CI. I. Inseda. 



N. 0. Diptera. 



Fam. CEst7'idce. 



Gen. (Estriis; the larvce of some species are 

 Entozoa. 

 CI. II. Araclinida. 



N. 0. Trachearia. 



Gen. Pentastoma. 



NEMATODA. 



Tliis order is treated o^ first because it includes the parasites 

 emphatically called " worms." Wlien a horse is said to have 

 worms, we know that in nine cases out of ten the animal is passing 

 lumbricoids of large size {Ascaris mcgaloccphala), or it is troubled 

 with maw^-worms {Oxyuris curvula). In like manner, when a 

 dog is said to have worms, it is either meant that the animal is 

 passing or throwing up round-worms {Ascaris marginata), or 

 that it is parting with the falsely so-called maw-worms, which, 

 after all, are neither more nor less than the free and independent 

 segments or proglottides of some species of tape-worm. Worms 



