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of the life-history of tapeworms in general, yet we now know 

 experimentally that the law is not only applicable to, but is 

 perhaps most forcibly illustrated in, the development of the 

 Cestoidae. The itinerary is as follows : Primarily, a six-hooked 

 embryo; second, the cysticercus; third, the scolex ; fourth, 

 strobila ; and, lastly, the sexual animal with the uterine pro- 

 glottis. These stages may be reduced to three : the six-hooked 

 brood, cysticercus, and mature worm. The author then gave 

 a short account of the work done by various investigators, 

 since von Linstow (1872), who, seeking and finding cysticercoids 

 in fresh-water copepods, cypriclae, annelidae, and insecta, and 

 comparing the hooks of the embryonic scolex with those given 

 by Krabbe for the mature worm, have endeavoured to establish 

 their identity. Mr. Rosseter said that credit is due to Dr. Stiles, 

 of Washington, who, in 1896, published his Tapeworms of 

 Poultry, for plainly stating that the comparison of the hooks 

 upon the heads of adult tapeworms in birds with the hooks of 

 larvae found in invertebrate bodies did not explain the life- 

 history, nor furnish the data which the science of the day 

 demanded, and that experimental infection with these supposed 

 larvae, and the production of the mature worm, was what was 

 required. After referring to the successful experiments of 

 Grassi and Eovelli in 1888-92, the speaker gave some particulars 

 of his own work in this direction. In 1891 he fed some ducks 

 with a characteristic larval tapeworm he found making Cypris 

 cinerea its host, and on killing the ducks, found them to be 

 infested with a tapeworm whose scolex bore the same charac- 

 teristic hooks as the cysticercoid. This was submitted to 

 R. Blanchard, of Paris, who formed a new genus and species for 

 it. Reference was also made by Mr. Rosseter that at the time 

 of the appearance of Stiles's work he had already infected ducks 

 with Taenia cornula, T. gracilis, and T. tenuirostris, and in each 

 instance produced the specific tapeworm. The speaker then 

 stated that while certain workers preferred the study of the 

 cysticercoid form, other helminthologists, including himself, had 

 turned their attention to the internal anatomy of avian tape- 

 worms, and for the following reasons. Primarily, the species 



