408 ENTOZOA. 



Wolf, Dog, Mink, and even Man, where it lies doubled up, dis- 

 tending that organ, destroying its parenchyma, and probably oc- 

 casioning the most excruciating agony to the animal in which it 

 resides. It has been occasionally known to pass off with the 

 urine, while yet small. It sometimes inhabits other viscera. Its 

 usual colour is a beautiful red ; the mouth is surrounded with six 

 papillae; the intestine is straight and transversely rugose, the 

 ovary simple, three or four times the length of the body, com- 

 municating exteriorly by a hole a little distance posterior to the 

 mouth, and, as it appears, by the other extremity, with the anus. 

 An extremely attenuated white thread that extends along the 

 abdomen is considered by M, Otto as the nervous system *. 

 Naturalists have lately separated from the Ascarides and Strongyli 

 the 



Spiropoptera, 

 Where the body terminates spirally, and is surrounded by two wings, 

 from between which issues the penis f- 



One species is said to be occasionally found in the liuman 

 bladder. Another, the 



Sp. struniQsa, Nitsch, inhabits the Mole. It penetrates into a 

 ring which it forms in the villous coat of the stomach, and at- 

 taches itself there by a small tubercle ;}:. 



PhysaLoptera, 

 Where the posterior extremity is provided with a bladder between two 

 little wings, and a tubercle from which the penis originates §. 



ScLEROSTOMA, Blainv., 

 Where the mouth is furnished with six small dentated scales. 

 They are found in the Horse and in the Hog. 



LlORHYNCHUS, Rud., 



Where the mouth is in the form of a little proboscis !|. 



Pentastoma, Rud., 



Where the body is depressed and trenchant on the sides, and the trans- 

 versal rugae are marked by numerous crenulations. The skin is thin 

 and slight ; the head broad and flattened ; and the mouth beneath ; on 

 each side of the latter are two small longitudinal clefts, from which 

 issue little hooks. The intestine is straight and the genital vessels 

 are long and tortuous. Both the former and latter open externally at 

 the posterior extremity. Near the mouth are two caeca, as in Echi- 

 norhynchus. A white thread encircles the mouth and gives off two 

 descending trunks, in which I think I have recognized the appear- 

 ance of a nervous system. 



* Otto, Magas., of the Soc. Nat. Berl., 1816, p. 225, pi. v. 



t Rud., Syn., p. 22. 



+ Nitsch, Moaog., Gm., Hal. Sax., 1829. 



§ Rud., Syn., 29. 



!l Rud., Hist. II, 247, et seq. 



