PARENCHYMATA. 507 



continuous parenchyma, the only ahmentary organ it contains being 

 ramified canals, which distribute nourishment to its different points, 

 and which, in most of them, originate from suckers visible exter- 

 nally. The ovaries are also enveloped in this parenchyma or that 

 cellulosity. There is no abdominal cavity, nor intestine properly 

 so called; and if we except some equivocal vestiges in the first fami- 

 lies, there is nothing to be found which bears a resemblance to 

 nerves. 



We may divide this order into four families. 



FAMILY I. 



ACANTHOCEPHALA.(l) 



The Parenchymata of this family attach themselves to the intes- 

 tines by a prominence armed with recurved spines, which also ap- 

 pears to act as a proboscis. They form the single genus 



ECHINORHYNCHUS, Gm. 



Where the body is round, sometimes elongated, and sometimes in the form 

 of a sac, provided anteriorly with a prominence in the form of a probos- 

 cis armed with little hooks bent posteriorly, and susceptible of being re- 

 tracted or protruded by the action of particular muscles. These worms 

 cling to the intestines by means of their proboscis, and frequently penetrate 

 through them, so that individuals are sometimes found in the thickness of 

 their tunics, and even in the abdomen, adhering to their external parietes. 

 E. gigas, Gm. The largest species known; it inhabits the intestines of 

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



FAMILY II. 



TREMADOTEA, Rud. 



Our second family comprises those which are furnished under- 

 neath 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 



(1) Thorn-headed. 



