ANNULOSA. 



41 



OJIDER III. NEMATODA (XEMATOIDEA\ 



Section A. Acrophalli. 



Fani. a. Trichocephalidse (Trichotrachelidte). 

 cephalus. 



Fam. 1. Trichinidse. Tri- 

 china. 



Fam. c. Strongylidae. Eu- 

 strongylus, Syngamus,Doch- 

 mius, Sclerostoma, 



Section B. Hypophalli. 



Fam. a. Spiraridse. Spirop- 



tera. 

 Fam. b. Cueullanidse (Cepha- 



lota). Cucullatms. 

 Fam. c. Filariidse. Filaria. 

 Fam. d. Ascarida. Ascaris, 



Oxyuris. 

 Fam. e. Cheiracanthidee. 



Cheiracanthus. 

 Fam. /. Anguillulidse. 



RMbditis (fig. 36), Tyl- 



enchus, Dorylaimus. 



The -genera Cheetosoma and Rhabdogas- 

 ter include certain singular, free-living, 

 marine worms, which have a close rela- 

 tionship in their internal anatomy with 

 the ordinary Nematodes, but which have 

 the peculiarity that the ventral surface 

 carries a double row of bristles placed in 

 front of the anus. If these types are 

 included in the Nematoda, they must be 

 regarded as forming a special section of 

 the order. 



Tricho- 



Fig. 36. Nematoda. A, Khabditis 

 bioculata, female, enlarged. B, Por- 

 tion of the alimentary tract of Oxyuris 

 vermicularis, enlarged: g, Gullet; v, 

 Muscular gizzard; s, Chylific stom- 

 ach, or anterior end of the intestine 

 (i) ; oo, Ovaries ; p, Genital pore. 



(Bastian, Monograph of the Anguillulidce or Free Nematoids, Linn. Trans., 

 1865 ; Schneider, Monographic der Nematoden, Berlin, 1866 ; Leuckart, 

 Die Menschlichen Parasiten, Bd. II., 1876.) 



