235 Two fairly mature proglottids of _Tænia solium_ 332 236 Head of _Tænia solium_ 332 237 Large and small hooks of _Tænia solium_. (After Leuckart) 333 238 _Tænia solium._ (After Leuckart) 333 239 Two mature proglottids of _Tænia solium_ 333 240 Large and small hooklets of _Tænia marginata_. (After Leuckart) 338 241 Mature segment of _Tænia saginata_ 339 242 Cephalic end of _Tænia saginata_ 339 243 _Tænia saginata._ (After Leuckart) 339 244 A piece of the muscle of the ox, with three specimens of _Cysticercus bovis_. (After Ostertag) 340 245 Mature segment of _Tænia africana_. (After v. Linstow) 342 246 Proglottis of _Tænia africana_. (After v. Linstow) 343 247 Head of _Tænia africana_. (After v. Linstow) 343 248 _Tania confusa._ (After Guyer) 344 249 _Tania confusa._ (After Ward) 344 250 _Tania echinococcus_ 345 251 _Echinococcus veterinorum._ (After Leuckart) 347 252 } 252A} Diagrams of mode of formation of brood capsule and scolices (Stephens) 348 253 Section through an invaginated echinococcus scolex. (After Dévé) 350 254 A piece of the wall of an _Echinococcus veterinorum_ stretched out and seen from the internal surface 350 255 _Echinococcus hominis_ in the liver. (After Ostertag, from Thomas) 351 256 Section through an echinococcus scolex in process of vesicular metamorphosis. (After Dévé) 351 257 } 257A} Diagram of transformation of a scolex into a daughter cyst. (Stephens) 352 258 Hooklets of echinococcus. (After Leuckart) 355 259 _Echinococcus multilocularis_ in the liver of the ox. (After Ostertag) 357 260 Diagram of a transverse section of _Ascaris lumbricoides_. (After Brandes) 362 261 Anterior end of an _Ascaris megalocephala_. (After Nassonow) 362 262 Transverse section through _Ascaris lumbricoides_ at the level of the œsophagus behind the nerve ring. (After Goldschmidt) 364 263 Schematic representation of the nervous system of a male _Ascaris megalocephala_. (After Brandes) 365 264 Diagram of female genitalia 368