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 Pendulaeia. 



Integument not ciliated and no spontaneous fission in the mature 

 worms. 



Genera : Monostoma, Amphistoma, Distoma, Diporpa (in conju- 

 gation Diplozoon), Gasterostoma, Holostoma, Tristoma, Polysioma. 

 {Gyrodactylus, Axine, Octobothriuniy Aspidocotylus, Aspidogaster, 

 are all, probably, larvae.) 



Sub-order Tukbellakia. 

 Integument ciliated in the mature worms. 



Family Hhabdoccela, with a simple cylindrical alimentary cavity. 



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

 sostomum, Macrostomum, Microstomum. (Some of these are, pro- 

 bably, larvae.) 



Family Dendroc(ela, with a ramified alimentary cavity. 

 Genera : Polycelis, Monocelis, 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 CGELELMINTHA. 



An alimentary canal suspended in an abdominal cavity. The 

 se^es distinct. 



Order Gordiacea. 



Body filamentary and cylindrical ; alimentary canal without anus. 

 Genera : Gordius, Mermis, ( Trichina, probably a larva). 



Order NEMAToroEA. 



Body elongated, cylindrical. Alimentary canal with both mouth 

 and vent. 



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

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

 Gnathostoma, Cheiracanthus, Lecanocep/ialus, TAorhynchus, Physa- '% 

 loptera, Sphcerularia, Anguillula. 



