68 ENTOZOA. 



CHAPTER V. 



NEMATODA. 



The Filaridas — Trichocephalus ajffinis considered as a type — Wilson's investigations 

 respecting its anatomical structure — The views of Kuchenmeister and of Eberth 

 regarding the characters presented by the reproductive organs, compared with 

 those severally entertained by Mayer, Eberth, and the Author— Embryonic develop- 

 ment — Genera — Simondsia paradoxa — Cheiracanthidas — Genera — Ascaridse — 

 Genera. 



FilaridcB. — The typical genus of this family has hitherto 

 served as a sort of refuge for destitute systematists puzzled 

 where to place numbers of filiform nematodes, whose characters 

 were only imperfectly known, or if known, were probably those 

 of immature ascarides. Even at the present time it is not 

 pretended that we are in a position to rectify many long 

 standing errors in Nematode classification, yet it would be ex- 

 tremely desirable to separate the round worms into tolerably 

 well defined family groups. In this work I offer an arrangement 

 presenting only the merest approximation to that which I hope to 

 see ultimately accomplished ; knowing full well that a true natural 

 grouping can only be obtained after a long-continued personal 

 examination of every available type. The genus Filaria is variously 

 defined by the most trustworthy entozoologists, and according to 

 the definitions of some would appear to be inseparable from the 

 Ascarides properly so called. Provisionally, I shall include in the 

 above family title all those nematodes presenting the following 

 characters : — body filiform, smooth or finely striated transversely, 

 furnished with a simple round or triangular mouth, generally sur- 



