8 INTRODUCTION 



much as I represented it in 1864; but in the present work I 

 cease to speak of the Entozoa as in any sense the zoological 

 equivalent of the Helmintha. I prefer to employ the term 

 Entozoa in its popular and wider acceptation. It conveniently 

 stands thus, moreover, in direct contradiction to the term 

 Ectozoa. 



As this work treats of parasites only, I purposely refrain 

 from dealing with the Turbellarians, and certain other creatures 

 usually classed with Vermes. The vague term " worms/' so 

 often employed as the equivalent of Hdmintka, is misleading in 

 many ways. I should like to see it adopted only when speak- 

 ing of the Annelids proper. It would still have a sufficiently 

 wide application, seeing that it would include Leeches, Earth- 

 worms, Naids, Tubed-worms, Sea-lobworms, Sea-mice, Nereids, 

 and a host of other setigerous species. Notwithstanding the 

 remote connection subsisting between "intestinal worms" 

 and worms properly so called, the notion that an intimate 

 relation subsists between the lumbricoid helminths and earth- 

 worms will probably never entirely disappear from the popular 

 or even from the professional mind. 



Since one of the principal features of this treatise is to afford 

 a handy means of reference to the rich and extended literature of 

 parasitism, I here subjoin a list of general and systematic 

 treatises. To most of these I shall constantly refer. Full 

 special references to detached memoirs will appear in the biblio- 

 graphies scattered throughout the body of the work. 



BIBLIOGRAPHY (No. 1 ) . Bremser, ' Ueber lebende Wiirmor 

 im lebenden Menschen/ Vienna, 1819 ; French edit., by 

 Grundler, 1824. Idem, ' Icones helminthium/ Vienna, 1824. 

 Colloid, T. 8., ' Entozoa, an Introduction to the Study of Hel- 

 minthology, with reference more particularly to the Parasites of 

 Man/ London, 1864; Supp., 1869. Reviews in the 'Lancet/ 

 Sept. 24th, 1864, p. 353; in the ' Med. Times and Gaz./ Oct. 

 29th, 1864, p. 474; in the ' Athenaeum/ Oct. 15th, 1864, p. 

 493; in 'Cosmos/ Oct. 27th, 1864, p. 463 ; in the 'Reader/ 

 Nov. 26th, 1864, p. 668 ; in the ' Edinburgh Vet. Review/ Nov., 



1864, p. 662; in 'Intellectual Observer/ vol. vi, 1864, p. 190 ; 

 in the ' Quarterly Journal of Science/ No. v, January, 1865, 

 p. 145 ; in the ' Quart. Journ. of Micr. Science,' New Series, 

 No. 17, Jan., 1865, % p. 43; in 'Popular Science Review/ Jan., 



1865, p. 214; in the 'Veterinarian/ Feb., 1865, p. 97; in the 

 < Medical Mirror/ Jan., 1865, p. 23; in the 'Natural History 



