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THOMPSON YATES LABORATORIES REPORT 
species described as occurring thus, are : — Gordius aquaticus, G. tolosanus, G. varius, 
G. chilensis. Probably they gain access to the alimentary canal of man and animals 
through the medium of drinking water. 
The Acanthacephala include, following Shipley, 2 four families: — Neorhyn- 
chidae, Gigantorhynchidae, Echinorhynchidae, and Arhynchidae. The adult forms 
have no alimentary tract, and are provided with a retractable proboscis, armed with 
hooklets, arranged in longitudinal rows. The adult stage occurs in the alimentary 
canal of vertebrates, generally those which live in or near water; while the larvae 
are found in the bodies of certain invertebrates, generally small Crustacea 3 , e.g., 
Gigantorbynchus gigas inhabits the small intestine of the pig, wild boar, and 
occasionally man, while the larval host is believed to be some species of beetle 
( Melolontha, Cetonia, and Lachnosterna ). G. echinodiscus inhabits the intestine of ant 
eaters ; G. spira of the king vulture ; Echinorhynchus proteus of fishes (gudgeon, trout, 
turbot, etc.) ; the larval stage in some Amphipod Crustacea, and some fresh water 
fishes (minnow, etc.). Other species of Echinorhynchus occur in the duck, dog, 
rabbit, some aquatic birds, and occasionally man. 
The Nematodes present very great difficulties to the systematist in their 
classification. Schneider 4 divided them into three groups : — (i) the Polymyarii, in which 
numerous muscle cells are seen in a transverse section ; (ii) th? Meromyarii, in which 
only eight are seen, two in each quadrant; (iii) the Holomyarii, in which the muscles 
are either not divided or only divided by longitudinal lines. Other classifications 
have been based upon the life history, but in many cases this is only very imperfectly 
known. At present the arrangement of the muscles (Polymyarii, Meromyarii, 
Holomyarii), the arrangement of the lips and mouth parts, the character of the male 
tail, the number of papillae, and the number and size of spicules, are the features 
which are relied upon for classification. Shipley 5 deems it advisable at present to 
abandon the larger groups, and to deal directly with families. Of these he quotes 
seven :— i Ascaridae. 
II. Strongylidae. 
III. Trichotrachelidae. 
IV. Filariidae. 
V. Mermithidae. 
VI. Anguillulidiae. 
VII. Enoplidae. 
We have considered it advisable to state briefly here the characteristic features 
of each of these families, and to describe shortly those forms of each family which 
are interesting to the student of human parasitology. 
2. Harmer and Shipley, The Cambridge Natural History, Vol. II, Worms, Rotifers, and Polyzoa. London, 1896. P. 182 
3. Harmer and Shipley, The Cambridge Natural History, Vol. II, Worms, Rotifers, and Polyzoa. London, 1896. P. 174. 
4. Schneider, Monographic der Nematoden. Berlin, 1866. 
5. Harmer and Shipley, The Cambridge Natural History, Vol. II, Worms, etc. P. 138. 
