PARENCHYMATA. 477 



animal feeds. Behind the sucker is a little retractile tentaculum, and posterior 

 to that, the second sucker ; extremely flexuous vesiculae scminales fill up the 

 centres of the leaf. The ovary, which is found in every individual, is set in 

 the intervals of the intestines, and the ova issue through a flexuous canal that 

 opens exteriorly by a small hole. 



The species that infest sheep become greatly multiplied when they graze in 

 low and wet grounds, rendering them dropsical, and finally killing them. 



M. Rudolphi, under the name of ECHINOSTOMA, makes a division of those 

 species which have a slight tubercle or swelling, anteriorly armed with hooks. 



HOLOSTOMA, Nitz, 



Where one half of the body is concave, and so arranged as to act altogether 

 like a cup. Their orifices appear to be similar to those of Distoma. 

 They inhabit certain birds. One species is found in the fox. In 



POLYSTOMA, Zed., 



Or rather Hexastoma, the body is depressed, smooth, and furnished with six 

 cups arranged in a transverse line, under the posterior margin. The mouth 

 appears to be at the opposite extremity. 



They have been found in the urinary bladder of frogs, in the ovary of 

 woman, on the branchiae of some fishes, and in the nasal cavity of certain 

 tortoises. 



CYCLOCOTYLE, Otto, 



Where there are eight cups forming an almost complete circle, under the hind 

 part of the body, vfhich is broad ; there is a small proboscis anteriorly. 



FAMILY III. 



TJENIOIDEA. 



IN our third family of parenchymatous intestinal worms, we place all those 

 species in which the head is provided with two or four suckers placed around 

 its middle, which is itself sometimes marked with a pore, and sometimes 

 furnished with a little proboscis, naked or armed with spines. Sometimes 

 there are four little trunks thus armed. 



The most numerous genus is 



T.KNIA, LinruBus, 



The body of the Tape-worm is often excessively elongated, flat, composed of 

 joints more or less distinctly marked, and narrowed anteriorly, where we 

 generally find a square head hollowed by four small suckers. 



Observers have thought that they could perceive canals which arose from 

 these suckers, and crept along the margin of the joints of the body. Each of 



