98 POCLTRV DISEASES 



Davainea Echinobothrida 



This tapeworm infests the small intestines of turkeys. It 

 has been found in tnrkevs in North Carolina. Its head is 



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sliti'litly larg'er than the n(^ck. is rounded in front and pro- 

 vided with four suekers and a circular rostellum of hooklets. 

 These hooklets are arranged in a double row. The hooks 

 lunnber about 200 and surround a pit-like cavity. This con- 

 stitutes its fixation apparatus by which means it holds on to 

 the mucous membrane of the l)Owel. These worms may reach 

 the length of six inches. The mode of spread of the parasite 

 and treatment of the birds are the same as in the fowl. 



Other Taeniae 



Two or three other species of tapeworms closely resend)ling 

 these in their gross appearance have been described, but judg- 

 ing from the records they do not appear to be connnon. Tape- 

 worms are also found in the intestinal tract of ducks and 

 other birds. 



THE THORN-HEADED WORMS 

 (Acanthocephala) 



The third class of worms listed belong to the order Acan- 

 thocephala. The body is cylindrical, but they are not pro- 

 vided with a complete digestive tract, as are the nematodes, 

 or round worms. They have transverse markings, and, like 

 the tapeworms, live by absorbing, through their integument, 

 nutrients eaten and digested by their hosts, thus, to a degree, 

 robbing them. Furthermore, when present in great numbers, 

 these parasites cause digestive derangements and emaciation 

 of their hosts. They are provided Avith a globe-shaped pro- 

 boscis, armed Avith hooklets, which they embed in the mucous 

 lining of the intestines; thus attached by their heads, their 

 bodies float in the intestinal contents. 



Echinorynchus Polymorphus 



This is one of the three species of this geiuis that live in 

 the intestines of the duck. Tt is also found in the goose. 



Description. — The Echinorjjuchus poUjmorphus varies in length 

 from one-fourth to one inch. The body is orange-red in color. It 

 has a neck-like construction, just back of the hooked, globe-shaped 

 proboscis. Its proboscis is provided with eight or nine rows of 

 hooklets. 



TAfp History. — This worm reproduces by laying eggs. The inter- 

 mediate host is certain fish, as the shrimp and crayfish. Ducks 

 become infested by eating fish infested by the larval or cystic form. 

 This parasite is probaoly rare in the T'nited States. 



