
AILMENTS AND DISEASES 

fishes. These are Cucullanus foveolatus of the sunfish, and C. elegans of 
the perch and the Cyprinide, Fig. go. 
Firarip#. These parasites are more common to 
the marine fauna. Fi/aria piscius is found spirally coiled 
within the tissues of the herring, cod and whiting. A 
number of other species of this family occur in similar hosts 
and in warm-blooded animals. 

Gorpib#. These parasites take up a free existence 
FIG. go. in damp earth and penetrate the bodies of insects and their 
Cucullanus elegans, 
a Nematod parasite. larvae. Some gain access to fishes by this means, where 
ee eae ae they become encysted in the tissues. 
ANGUILLULID&. These minute free intestinal thread- 
worms usually have the higher Vertebrates as hosts, but some species are 
parasitic in aquatic molluscs and in insect larve. They are very widely 
distributed; the so-called Vinegar-eel, Auguillus aceti, belongs to this order. 
All the other families of this group are parasites of higher Vertebrates. 
ACANTHOCEPHALA OR THORN-HEADED Worms. This group con- 
sists of members having vermiform bodies and otherwise resemble the 
Nematoda, but differ in having spine-covered heads by which they attach 
themselves to their hosts. They are now included in the single family 
Echinorhynchide, which infests all classes of Vertebrates and are one of the 
more frequent parasites of fishes and amphibia. Over 100 species have 
been described, a considerable number in the Cyprinide; and of these 
Echinorhynchus proteus is the most abundant species, of which the 
immature form inhabits the smaller crustaceans, especially Gammarus 
and Asellus, to be transferred with them to freshwater fishes. Other 
FIG. 91. 
Echinorhynchus pro- 
teus, an Acanthoce- 
phalous parasite. 
Intermediate and 
Adult forms. 
Greatly enlarged. 
FIG. 92. 
Echinorhynchus 
angustatus, an 
Acanthocephalous 
parasite. Length 
22 to 25 mm. 
Enlarged. 
Fig. 93. 
Echinorhynchus 
anthuris, an Antho- 
cephalous parasite. 
Greatly enlarged. 

common forms are E. angustatus, E. claveceps, E. anthuris, E. globulosus, 
and E. tuberosus in the Salmonide and similar fishes. Some of these and 
E. clavula, E. fusiformis and E. pachysoma frequently occur in other fresh- 
water fishes, principally the Cyprinidae. £. anthuris also occursin the Water 
newt, and E. inflexus in the Snapping turtle. The Echinorhynchide cause 
150 
