PARENCHYHATA. 413 



a prohoscis, armed with little hooks bent posteriorly, and susceptible of 

 being retracted or protruded by the action of particular muscles. At 

 its extremity we sometimes observe a papilla or pore which may be an 

 organ of absorption, but it is certain that if the animal be plunged 

 into water it becomes universally distended, and absorbs that liquid 

 through the whole surface, on which it is thought we can discover a 

 network of absorbent vessels. No other parts that can be compared 

 to intestines are visible internally, than two slightly elongated caeca 

 attached to the base of the tuLiform prominence ; a vessel extends 

 throughout its length on each side. A thread that runs along the 

 inferior face of the animal is considered by M. dc Blainville as its 

 nervous system; but neither Ruclolphi nor Cloquet coincide with him. 

 Certain species have a distinct oviduct; in others the ova are disse- 

 minated tlu-oughout the celhdosity or parenchyma of the body. The 

 nfales are provided with a little bladder at the end of the tail, and 

 very distinct internal vesiciilre seminales. We may believe that they 

 fecundate the ova afcer they are extruded. 



These worms cling to the intestines by means of their proboscis, 

 and frequently penetrate through them, so that individuals are some- 

 times found in the thickness of their tunics, and even in the abdomen, 

 adhering to their external parietes. 



E. gigas, Gm.; Gcetz., X, 1—6; Encyc. XXXVII, 2—7. The 



largest species known; it inhabits the intestines of the Hog and 



Wild Boar, where the females attain a length of fifteen inches *. 



Certain species, in addition to the prickles on their proboscis, are 



armed with them in some otlier part of the body. 



ILeruca, Gm., 

 Only diifering from Echinorhynchus in the prominence, which is re- 

 duced to a single crown of spines, terminated by double hooks. 



H. muris,Gn\.; EcJnnorliynchus hccruca, Rud. ; Goetz., IX, 

 B., 12; Encyc, Vers, XXXVII, If. It inhabits the liver of 

 Rats. 



FAMILY II. 



TREMADOTEA, Rud, 



Our second family comprises those which are furnished underneath 

 the body, or at its extremity, with organs resembling cupping-glasses, 

 by which they adhere to the viscera. 



They may all be united in one genus, or the 



Fasciola,L2«., 



Which may be subdivided in the following manner, according to the 

 number and position of their organs of adhesion. 



* For the other species see Rud., Hist. II, 251, and Syn., p. 63. 

 t Id., lb., 292, et seq. 



