312 T. B. ROSSETER ON CYSTICERCUS VENUSTA. 



I think I have clearly shown the differences that exist 

 between the hooks of T. fragilis, T. fasciata, and the hooks of 

 this new Taenia ; and that although the rostrum of the latter, 

 like the former, bears eight hooks, and must be classed with 

 them numerically, still it must be admitted that they, both of 

 the Taenia and Cysticercus, are totally distinct from Fasciata 

 and Fragilis in their specific character. This decision is like- 

 wise supported by the differences existing between the two 

 Cysticerci (Figs. 1 and 12), the long diameter of C. fasciata being 

 0*13 mm. less than that of the new Cysticercus. 



Having thus made it clear that this Cysticercus is not iden- 

 tical with that of either of these " six " species of tape-worm 

 with "eight hooks" on the rostellura, and that the tape worm 

 in question is the perfected scolex of this Cysticercus, I con- 

 sider I have proved it to be, both by experiment and demonstra- 

 tion, an entirely new tape-worm and Cysticercus, and therefore 

 I feel justified in giving them a specific value, viz., 



Tamia venusta, n. sp. (Rosseter). 



= E = 

 Cysticercus venusta, n. sp. (Rosseter). 



T^NIA. 



Number of hooks on Rostrum, 8, arranged in a single row. 

 Size of hooks, 0051 mm. -0'054 mm. a-b, 0'024 mm. ; a-c. 

 0051 mm. 



Length of a- 6, constant. 



Habitat, intestine of domestic duck. 



CYSTICERCUS. 



Number and size of hooks same as in Taenia. 

 Diameter of cyst— long axis, 0'27 mm. ; median, 024 mm. 

 Parasitic in body cavity of Cypris cinerea. 

 Locality, Langham House Pond, Gorstly Wood, Bishops- 

 bourne, near Canterbury, Kent. 



Reference to Figs, on Plates XIV., XV. 



FlG. 1. Cysticercus, a, Embryonic Scolex; 6, Suckers; c, Ros- 

 trum ; d, Hooks ; e, Cuticle ; /, Fluid-cavity ; g. 

 Caudal appendage, x 175. 



