ECHINOSTOMA. ENTOZOA. 409 



TRIBE II. ECHINOSTOMA, Lat. 

 Mouth armed with teeth or hooks, and the body rarely filiform. 



Gen. SCLEROSTOMA, (first division of the genus Strongylus of Rudolphi ;) 

 SAGITTULA, POROCEPHALUS, ECHINORHYNCUS, H^RUCUS, PRIONO- 

 DERMA, (Pentastoma, Linguatula, and Tetragulus^ Rudolphi.) 



ORDER II. ELMINTHAPROCTA. (Worms without 



anus.) 



Worms inhabiting the interior of the bodies of different ani- 

 mals ; sexual organs united in each individual ; no floating 

 alimentary sac, but a simple cavity in the interior ; and al- 

 most or totally destitute of nerves. 



FAMILY I. HIRCJDIFORMIA. 



Sexual organs distinct ; body not inclosed in a cyst, nor ter- 

 minated posteriorly by a bag, soft, depressed, more or less re- 

 sembling that of a leech, with suckers, of which one or more 

 serve as the mouth. 



The animals of this family are extremely numerous, and have the faculty of at- 

 taching themselves by suction to the internal parts of other animals. They have 

 in general an oblong body, with two suckers, of which one is at the anterior ex- 

 tremity, and the other on the side or under the belly. The Fasciola hepatica 

 Lin., one of the most common, is found in the liver of domestic animals, and chief- 

 ly of the sheep. While in small number they may be borne without much injury ; 

 but when they exist in great quantity, and fill the biliary canals, they produce serious 

 disease. 



TRIBE I. OLIGOPORA. 

 With one or two suckers. 



Gen. FASCIOLA, STRIG^US (Amphistoma) ; FESTUCARIA, (Monostoma) ; 



GEROPHL^US. 

 To this tribe belong the genera Hypostoma, Alaria, and Lobostoma, of Bremser. 



TRIBE II. POLYPORA. 

 With at least three suckers. 

 Gen. TRISTOMA, POLYSTOMA. 



FAMILY II. CESTOIDEA, Rudolphi. 



With sexual organs, or at least distinct ovaries ; body long, and 

 often articulated, not inclosed in a cyst ; mouth either con- 

 sisting of four trunks, or osculi surrounding a proboscidiform 

 mamilla or pore, with small spines in some and simple hooks 

 in others. 



The animals of this family are all intestinal, and one genus, Toenia^ has long been 

 known as infesting the human body. The tape-worms have an elongated body, of- 

 ten to an excessive degree, flattened, more or less marked by articulations, narrowed 

 anteriorly, and having a square head with four small suckers. The Tcenia lata of 

 Rudolphi has the joints broad and short and a double pore in the middle of each 

 lateral face. It is commonly about twenty feet long, and has been found to exceed a 

 hundred. It is very tenacious of life, and it requires the strongest medicines for its 

 expulsion. The ancient physicians believed that if any of the joints of the Tcenia were 



