46 NATURAL HISTORY SOCIETY OF DUBLIN. 



which, neither nerves, blood-vessels, nor any distinct or special element, 

 could be seen.* He drew attention to a very marked peculiarity in this 

 entozoon, the presence of two genital orifices, on one face of each arti- 

 culation, which evidently conduct to the ovary situated in each seg- 

 ment. These orifices are one above another in the direction of the axis 

 of the body, and form a linear series of dots down the median line. 

 Leblonde made of this worm a genus Prodiccdia ditrema, on account of 

 this arrangement of the genital pores. 



Creplin mentions having seen this worm in 1828, under the name of 

 Dihotlwius locetigridis, mRudolphi's collection,! and, finding fault with 

 the names already given it proposes Solenophorus as a more correct de- 

 nomination. There is a specimen of a worm apparently similar in the 

 Museum of the Royal College of Surgeons, England, taken from the in- 

 testines of a large serpent, ten feet in length, called at Exeter 'Change 

 Boa constrictor, but which belonged to the Genus Python of Dandin : 

 spec. 206 c, labelled Bothriocephalus Pythonis (sp. dub.). 



It is not improbable that these cestoid worms were derived from the 

 rabbits on which the Boa was principally fed, for it is well known how 

 prolific a source of tape-worm the flesh of the Rodentia is. The vesi- 

 cular entozoon, known by the name of Cysticercus pisiformis, is a very 

 common inhabitant of the liver and peritoneum of hares and rabbits. 

 Cysts as large as a hazel-nut are frequently disseminated completely 

 through the substance of the liver of hares, and are sometimes found 

 hanging down like bunches of grapes from the external surface of that 

 gland ; in rabbits the great omentum and the mesentery are generally 

 full of these cysts, each containing one, and sometimes two, Cysticerci. \ 

 The cystic worms constitute a necessary step in the development of the 

 tape- worm; for if these cysts or their contents are devoured by a dog, 

 in twenty-five days, as proved by experiment, they will have become 

 Tseniee of from ten to twelve inches long ; and, when fully grown, will 

 turn out to be the Tcenia scrrata, long known to infest the intestines of 

 dogs, and especially of hunting dogs, which are more in the way of 

 getting at rabbits and hares than parlour or lapdogs, which are usually 

 infested by the Taenia cucumerina.§ If a diseased rabbit or hare be 

 eaten by a gamekeeper or a poacher, the cystic worms will become de- 

 veloped within their human host into the Tcenia solium. If this same 

 cystic worm be eaten by a cat, the jointed tape- worm will not be de- 

 veloped at all — the Cysticercus will die in a short time; for every species 

 thrives and undergoes its metamorphoses only in a particular species of 

 animal. 



The metamorphosis experienced by the Cysticercus pisiformis of the 

 Rabbit, when swallowed by the Python or Boa, probably resulted in the 

 formation of this peculiar entozoon, the Solenophorus megacephalus ; for 



* " Annales des Sciences Naturelles," 1833, tome vi., p. 299. 



t "Allgemeine Encyclopedia," 1839. 



% Siebold " On Worms," p. 59. § lb., p. 61. 



