Cystoid Worms into Tcenias. 433 



hibited the articulations, and the point torn by the loss of the 

 vesicle actually presented a cicatrix. 



After twenty or twenty-five days, the worms were several 

 inches in length ; they were articulated to the extremity of the 

 abdomen, and the last of their joints still bore the cicatrix above 

 mentioned, which was still very perceptible ; traces of sexual 

 organs even were already to be discovered in the posterior seg- 

 ments. 



At the end of eight weeks the worms had attained a great 

 length (the longest were from 36 to 39 inches). The sexual cha- 

 racter of their posterior segments was completely developed, a 

 great number of ova in a state of maturity being contained in 

 them. Some individuals had already separated their last joints 

 in a perfectly mature state. 



In the Cysticercus pisiformis thus elongated, I recognized the 

 Tcenia serrata of the dog. The extremity of the head, the form 

 of the segments, the nature of the organs of generation, and 

 above all of the mature ova of this worm, agreed exactly with 

 the same parts of the Tcenia serrata. There was no longer there- 

 fore any doubt that the Cysticercus pisiformis of the hare and 

 rabbit is to the Tcenia serrata of the dog, what the Cysticercus 

 fasciolaris of the mouse and rat is to the Tcmia crassicollis of the 

 cat. 



The Tcenia serrata is rarely found in watch-dogs or house-dogs, 

 but more commonly in coursing dogs, which is easily explained 

 by the fact that the latter frequently devour the intestines of 

 hares and rabbits captured in the chase, and consequently swallow 

 the Cysticercus more frequently than other dogs. 



Although the experiments with the other worms above men- 

 tioned are not yet completed, those relative to the Coenurus cere- 

 bralis are sufficiently advanced to convince me that this worm, 

 so dreaded by the sheep farmers, becomes transformed into a 

 Taenia in the intestines of the dog. As yet, the Tsenias thus pro- 

 duced by the Coenurus cerebralis have not, in my experiments, 

 arrived at the adult state, the sexual organs not being yet ma- 

 ture j it is therefore impossible to determine the species to which 

 they belong, but I hope shortly to be able to do so. I hope also 

 that I shall be able to indicate to those interested in the raising 

 of sheep, the means of opposing the development of this parasite 

 in the brain of that animal, for I am convinced that the cystoid 

 worms are not produced by a local generation, but by the mi- 

 croscopic ova of the tape-worms of certain Carnivora, and that 

 when these ova are accidentally introduced into the bodies of 

 Rodent or Ruminant animals, they are not developed there into 

 elongated tape-worms, but into cystoid worms, which, according 

 to the importance of the organ in which they take up their 



Ann. ^ Mag. N. Hist. Ser. 2. Vol.x. 28 



