118 LECTURE VI. 



tary canal is continued, rarely provided with a vent. Male and 

 female organs in the same individual ; impregnation by reciprocal 

 coitus. 



Sub-order Pendularia. 



Integument not ciliated and no spontaneous fission in the mature 

 worms. 



Genera : 3Ionostoma, Amphistoma, Distoma, Diporpa (in conju- 

 gation Diplozoon), Gasterostoma, Holostoma, Tristomay Polysioma. 

 (^Gyrodactylus, Axine, Octohothrium, Aspidocotylus, Aspidogaster, 

 are all, probably, larvae.) 



Sub-order Turbellaria. 

 Integument ciliated in the mature worms. 



Family Rhabdoccela, with a simple cylindrical alimentary cavity. 



Genera: Vortex, Derostomum, Gyratrix, Strongylostomum, Me- 

 sostomum, 3Iacrostomum, Microstomum. (Some of these are, pro- 

 bably, larvae.) 



Family Dendroccela, with a ramified alimentary cavity. 

 Genera : Polycelis, 3Ionocelis, Planaria, Leptoplana, Eurylepta, 

 Planocera, Thysanozoon. 



Order Acanthocephala. 



Body saccular, cylindrical, or subdepressed ; head provided with 

 ,an uncinated proboscis. A ramified vascular nutritive system. 

 Sexes distinct. 



Genus : Echinorhynchus. 



Class CCELELMINTHA. 



An alimentary canal suspended in an abdominal cavity. The 

 sexes distinct. 



Order Gordiacea. 



Body filamentary and cylindrical ; alimentary canal without anus. 

 Genera : Gordius, 3Ier?nis, ( Trichina, probably a larva). 



Order Nematoidea. 



Body elongated, cylindrical. Alimentary canal with both mouth 

 and vent. 



Genera : Filaria, Trichosoma, Trichocephalus, Spiroptera, Stron- 

 gylus, Ascaris, Oxyurus, Cucullanus, Hedrurus, Ancyracanthus, 

 Gnathostoma, Cheiracanthus, Lecanocephalus, Liorhynchus, Physa- 

 loptera, Sphcerularia, Anguillula. 



