200 TAPEWOEMS OF HARES AND RABBITS STILES. 



and healthy ones, as well as those that were weak and lean, disclosed the fact that 

 they were almost without exception infected with tapeworms, which were found in 

 the duodenum and gall duct. In the latter they were frequently so numerous as to 

 close it up, and cause a suspension of its functions. 



For the purpose of continuing his studies Mr. Curtice brought from the West a 

 number of lambs, which were killed at intervals and their viscera examined, and 

 this material having been exhausted, and it being inconvenient and expensive to 

 obtain more, he turned his attention during the past winter to a study of the early 

 stages in the life of the Tcenia pectinata (common unarmed tapeworms of the rabbit). 

 In studying these Mr. Curtice thinks he has made some interesting discoveries, 

 which he presented to the Biological Society of Washington at a recent meeting. 



The variety examined is found abundantly in nearly all rabbits in this locality. 

 The life-history of the armed tapeworms of man and dogs has long been written, 

 but that of the unarmed species inhabiting our domestic animals, especially cattle 

 and sheep, is as yet comparatively unknown. As far as has been ascertained, the 

 life-history of the Tcenia pectinata is embraced in two stages. The first covers the 

 development of the ova into the embryo, which is ready to leave the parent Tcenia; 

 the other covers the period of growth from the youngest forms yet found in rabbits 

 to the adult stage. The life of the Tcenia from the time they leave the first rabbit 

 as an embryo until they are found as young Tcenia in the second rabbit infected has 

 as yet been unascertained. Among the theories that have been advanced is one 

 that they pass this stage upon the ground, are eaten by insects, snails, or crusta- 

 ceans, and that these are then eaten by the rabbits. This, however, is only a theory, 

 as none have ever been found in snails, insects, or crustaceans. 



It was Mr. Curtice's good fortune to find a rabbit which had recently been infected 

 with these peculiar parasites, none of which ^ere over 3 centimeters in length, 

 many of them being less than 5 millimeters long. There were more Twnia in that 

 rabbit than any he had ever seen before about 85. Among the smaller Tania were 

 several specimens that showed the stages of development from nonsegmented, armed 

 forms, to segmented, unarmed forms. Mr. Curtice showed "to the society specimens 

 illustrating the different stages. 



The youngest forms detected were not the smallest, but measured about one-half a 

 centimeter in length. They contained, in addition to the four suckers, a cup-shaped 

 cavity in the place of the rostellum. Around the border of this cup-shaped cavity 

 were situated 85 or 90 hooks. The older specimens show a similar cavity with no 

 hooks. Still older ones show no cavity at all. All of these were in the nonseg- 

 mented stages, but other forms, some of them smaller, were without signs of hooks, 

 and had already begun segmentation. 



Mr. Curtice compared these stages with similar stages in Twnia seraia [serrata~\, 

 and said that the youngest stage of the Tcenia pectinata was probably a cysticercoid 

 stage and not the cysticercal, and that this was indicated by the cup-shaped cavity 

 in the youngest forms of the Tcenia pectinata. 



In discussing the classification founded on the presence or absence of hooks, he 

 declared it to be incorrect, since the discovery described above shows that the 

 unarmed species in adult stages are armed in earlier stages. 



The speaker exhibited some elegant drawings made by Dr. George Marx, illus- 

 trating the embryo as it leaves the parent Tcenia. This embryo is six-hooked and 

 surrounded by a curious pyriform envelope, to which there is a double prolongation, 

 surmounted by a cap of the same substance. This cap has a shredded border, and 

 is believed to be the remnants of a mass which, in an earlier stage, completely sur- 

 rounded the embryo. This peculiar envelope has been previously noticed in Italy 

 by Perroucito [Perroucito] and in France by Raillet [RaillietJ. This stage is 

 similar to that found in Tcenia expansa, the unarmed tapeworm in sheep. 



This article was copied in the Texas Live Stock Journal, 1 but, owing 



'April 14, 1888. 



