1862.] DR. T. S. COBBOLD ON HUMAN ENTOZOA. 289 



15. Filaria lentis, Diesing. 



16. Strongylus bronchialis, Cobbold. 



17. Eustronff7/lus ffiffas, Diesmg. 



18. Sclerostoma duodenale, Cobbold. 



19. Spii'optera hominis, Rudolphi. 



20. Oxyuris vermicularis, Bremser. 



21. Tcenia solium, Linneeus. 



22. mediocanellata, Kuchenmeister. 



23. acanthotrias, Weinlaud. 



24. Jlavopuncta, Weinland. 



25. marginata, Batsch. 



26. echinococcus, Siebold. 



27. nmia, Siebold. 



28. elliptica, Batsch. 



29. Bothryocephalus latus, Bremser. 



30. cordatus, Leuckart. 



In this list it will be observed that I have purposely omitted the 

 Acarine ^Q\i.\xs>Pentastoma, the A.nnQ\\diDacfylius aculeatus (Curling), 

 and several other internal parasites not strictly referable to the Hel- 

 minths. 



Up to the present hour no one has recorded the occurrence of any 

 acanthocephalous helminth within the human body, although it is 

 well known that Echinorhynchi have been found in all the vertebrate 

 classes, and even in the Simiadce*. 



1. Fasciola hepatica, Linnseus. 



F. hepatica, Linnseus, Pallas, Fabricius, Miiller, Frohlich, Bosc, 

 Blanchard, Cobbold, &c. 



F. humana, Gmelin. 



Distoma hepaticum, Abildgaard, Zeder, Mehlis, Rudolphi, Brem- 

 ser, Delle Chiaje, Dujardin, Creplin, Siebold, Owen, Pluskal, Kii- 

 chenmeister, Diesing, Weinland, Simonds, &c. 



Planaria latiuscula, Goeze. 



The general structure of this parasite is now thoroughly well 

 understood, although some minor points, more especially in respect 

 of the mode of origin of the branches of the water- vascular system, 

 remain to be investigated. The old view of Mehlis, as to the termi- 

 nation of the excretory system by an open foramen caudate, although 



* In connexion with this subject I may remark that I have just received 

 (Nov. 1st) a most interesting brochure from Prof. Rudolf Leuckart, in which 

 he describes a remarkable series of genetic changes discovered by him as occur- 

 ring in Echinorhynehus proteus. Contrary to our previous notions, he proves by 

 experiments (with eggs administered to the Gammarus pulex of our ponds and 

 rivers) that the embryos materially differ from the adult forms, and stand iu the 

 same relation to them that the larval Pluteus and Pilidium respectively do to 

 Ophiurus and Nemertes. An alternation of generations was certainly quite un- 

 suspected. The title of the paper is " Helminthologische Experimentaluntersuchun- 

 gen," having been communicated to the Gottingen konigliche Gesellschaft der 

 Wissenschaften on the 9th October, 1862. Prof. Busk has since given a trans. 

 lation of this paper in the ' Microsc. Journal' for January 1863. 



Proc. Zool. Soc— 1862, No. XIX. 



