56 



its original home is said to be the rat. Dochmius duodcnalis is 

 another parasite from which one fourth of the population of 

 Egypt suifers more or less, and often fatally. The great kidney - 

 worrn of dogs and wolves, Strongylus gigas, attains a length of three 

 feet. It has been also met with in man. 



Chcetosoma (the Rhabdophora of Claparede), in some respects 

 resembling Sagitta, is, with Cystoopsis and Desmoscolex, obscure 

 forms, placed as pendants to this order by Schmarda. 



The following list of families and genera is from Glaus. He, 

 however, has not mentioned certain genera which for Diesing 

 and, after him, Schmarda are the types of families, i. e. Hedruris, 

 Cheiracanthus, and Ophiostoma (=Dacnitidae). For the two 

 families of free Nematoids Anguillulidae and Enoplidse (many 

 species of both are marine) Bastian adopts thirty genera in his 

 monograph of the Anguillulidee. 



Ascaridce. 

 Oxyuris. 

 Ascaris. 

 Heteracis. 



Strongylus. 

 Syngamus = Sclero- 



stomum. 

 Dochmius. 

 Ollulanus. 

 Physaloptera. 

 Cucullanus. 



TrichinidcB. 

 Trichina. 

 Trichocephalus. 



Filariidte. 

 Filaria. 

 Spiroptera. 

 Ancyracanthus. 



Mermididcs. 

 Mermis. 

 Sphaerularia. 



GordiidcB. 

 Gordius. 



Anguillula. 

 Tylenchus. 

 Ehabditis. 



Enoplidfs. 

 Dorylaemus = Uro- 



labes. 



Enchelidium. 

 Enoplus. 



Ehabdogaster. 

 Chastosoma. 



Order II. ACANTHOCEPHALA. 



Internal parasites, worm -like, the anterior end armed with re- 

 curved hooks. No mouth nor alimentary canal. Sexes distinct. 

 The water-vascular system is said to have no external openings. 

 The embryos are like Gregarinida, and become encysted as in 

 Cestoda ; in that state they are swallowed by birds, fishes, &c., 

 when they develop into mature animals. There are about 100 

 species. 



Echin orhynckida. 

 Echinorhynchus. 

 Coleops. 



