NEMATOIDEA. 645 



appears red from the blood with which the intestine is usually gorged. An analogous species, found on the Bel, 

 was long mistaken for the young of that animal. 



OphiottomtU, have the body formed as in the preceding, hut the mouth cleft across, which gives the appearance 

 of two lips. U. eyttidieola, is found in the air-bladder of some Fishes. 



Ascaris (the Ascarides), — 

 Nave the body round, and slender toward each extremity. The mouth is furnished with three fleshy 

 tubercles, among which there is a short tube, which the animal can protrude as occasion requires. 



The species are numerous, and inhabit the intestine! of many animals. The females, which are far more 

 numerous than the males, have the intestinal canal straight, and an ovary divided into two branches, which is 

 several times longer than the body, and opens by a Bingle oviduct at about one-fourth of the length from the 

 anterior extremity. The males have also a single vessel, \ery long, and with the external organ, which is near 

 the tail, sometimes double. Two white filaments, one extending along the back, and another along the belly, 

 have been considered as nerves ; and two thicker ones, extending along the right and left tides, have been con- 

 sidered as muscles, as a circulating system, and even as a breathing apparatus. Some species, as .t.litmhriro'ides, 

 have the bead without lateral membranes. This species is found, without any remarkable difference, in Man, in 

 the Ox, the Hog, and all the varieties oi the Horse family ; it has sometimes occurred fifteen inches in length. It 



is naturally of a white colour; and. fi what has been said of its reproductive organs, its power of multiplication 



is excessive. It occasions disease, and even death, especially in children, or in all cases where it ascends from 

 the intestines into the stomach. A. vermicularit, which has a small membrane on each side of the head, is very 

 common in children, and also in adults, when afflicted with certain diseases. It chiefly inhabits the rectum, at 

 the extremity of which it causes intolerable itching. Its length i3 not more than half an inch, and its body is 

 thickest in the anterior part. It is an exceedingly active little animal, and derives its name from the Greek verb, 

 " to leap, or move." 



Strongylus, — 

 Have the body round, and the vent of the male inclosed in a sort of purse variously formed, which is 

 regarded as the sheath of the organ of generation, which can be protruded from it. The female is 

 without this apparatus, and thus more nearly resembles the Ascarides. 



Some species have the mouth ciliated, or toothed, among which is 8. equintu, which is about two inches long, 

 With a hard Bpherical lead, small soft spines round the mouth, anil three lubes in the caudal appendage. It is 

 very common in the intestines of the Bone ; and, so far as is known, in those of all the solipede family of pa- 

 chydermatous animals. Sometimes it makes its way to the arteries, and there occasions aneurisms, and other 

 unpleasant diseases. 



Othi have the mouth with tubercles, or papillae, and among these one of the most remarkable is 



8. gigcu, the largest worm which is known to inhabit the intestines of any animal. It grows to the length of two 

 or three feet, and is as thick as the little finger. It is usually found in the kidneys of various animals, as the 

 Wolf, the Dog, the Marten, ami even Man; where it is coiled up, and inflates the organ, causing great pain. 

 Sometimes small ones pass oft" with the urinary discharge. It is not, however, confined to the kidneys, bat is 

 met with 111 other viscera. Its usual colour is a tine red ; the mouth has six papilla:; the intestine is straight, 

 with cross furrows ; the ovarj is simple, and three or four times the length of the body, it is understood to have 

 ■ posterior opening, and also one neai the mouth. M. ( )t to has considered a slender white thread, which p | 

 along the abdomen, as being the nervous system. 



Spiroptenu, have been separate,! from the Ascarides. Thej have the termination of the body spiral, with two 

 wing-like membranes, between which is the reproductive organ. One species is occasionally found in the human 

 bladder, and another in the stomach of the Mole,— to the villous coat of which it ait.u Ins itself by a small tubercle. 

 Phgtoloptera, has a small bladder between the wing-like membranes. 8derottoma, has the moutb (tarnished 

 with six small scaly plates, [t is found in the Morse and the Hog i.iur/ti/nc/ius, has the mouth in the form ol ■ 



Is, With Which it penetrates the cavity of the vis. era. 



Pentattoma, have the body flattened, and sharp in the sides, and the transverse ruga crenulated. The skm is 

 thin and weak i the head broad and flat, with the moutb beneath, and a longitudinal slit on each side, from which 



issue the books wherebj the animal adheres The intestine is straight, and the reproductn pans long and 



tortuous, a white filament surrounding the mouth, and two filaments which proceed from I to be the 



nervous svstem. One species, /'. t.riiiu'idiit, OCCUR m the frontal sinuses of the Mor>e and Dog, and attains a 

 length of about six inches. Ptionoderma, resemble the former, only the mouth is terminal, and has two 

 small bOOka. 



Cuvier includes the following genera of intestinal worms in this order, but gives it as his opinion that, 

 when tl.ev aie bitter known, they will require subdivision as a distinct family, 



I.I I'.N l v, — 



Have the body resembling the former both in its external and its internal 01 00 ; but it is pro- 



longed into a sort oi" neck of a hornj consistency, at the end of which is the mouth, various!] armed 

 with plate-like appendages. It insinuates the mouth and these appendages into the gills of fishes, 



