TRANSMIGRATIONS AND METAMORPHOSES. 231 



parasite, and whose history has only been known for 

 a few years. Chabert discovered the first species of this 

 group in 1787 in the frontal sinus of the horse and 

 the dog. It had been named Tsenia lanceolata. All 

 naturalists, Cuvier included, placed this animal among 

 intestinal worms, under the name of Linguatula or 

 Pentastoma, The latter name had been given to it, 

 because they mistook the hooks for mouths. 



We have shown, from the embryos, in 1848, that 

 the Linguatulae, instead of being worms, are articulate 

 animals, more allied to the lerneans or acarid^ than 

 to the helmintha. These observations, though received 

 at first with much hesitation, were fully confirmed after- 

 wards, especially by the learned researches of Leuckart. 

 The linguatulae have a very long body, sometimes 

 rounded, in other cases compressed, with a mouth 

 sm-rounded by four strong hooks, regularly disposed in 

 a semicircle. They have often been found in the lungs 

 of serpents, in certain birds, and in many mammals. A 

 linguatula was also seen by Bilharz at Cairo, in the 

 liver of a negro, and they have been observed in the 

 hospitals of Dresden and Vienna. 



It is to be presumed that this dreadful parasite has 

 been introduced into man by means of the flesh of 

 the goat, and perhaps of the rabbit. Linguatulse 

 are found in their primary agamous form, in open 

 cavities Hke the nasal fossae. Leuckart was the first 

 to show that the hnguatulae, which lived at first 

 encysted in the peritoneum of the rabbit, completed their 

 evolution and became perfect in the nasal fossae of 

 the dog. The Linguatula serrata (Fig. 65), which Hves 

 primarily in the goat, the guinea-pig, the hare, the 



