56 ENTOZOA. 



narrowed, terminating in a slightly abrupt truncate point, tlie 

 moutli being central, simple, and unarmed. The pharynx is pro- 

 longed backwards into a strong, spherical, muscular, oesophageal 

 bulb ; the latter being succeeded by a long, cylindrical, intestinal 

 tube wliich ends in a distinct anal opening, placed a little above or 

 at the basal portion of the tail. Some regard the oesophageal bulb as 

 the stomach, and all recognize, within it, a special dental apparatus. 

 The tail is conical and finely acuminate, that of the male being sup- 

 plied with two intromittent spicules of equal length. In the female, 

 which produces its young viviparously, the vaginal outlet is situated 

 a little beyond the posterior third of the body. As in other Nema- 

 todes, the uterus early divides into two oviducal tubes, in the 

 interior of which the young embryos may be seen either free or 

 still enclosed within their egg-shells. 



Genera. — Anguillula, Ehrenberg ; =BhabditiSi Dujardin ; = (in 

 part) Vibrio, Miiller ;=Bnchelidium, Ehrenberg ; Fontonema, Leidy ; 

 Enoplus, Dujardin; TJrohales, Carter; Amblyura, Hemprich and 

 Eln-enberg ; = Enchelis, Hill, Oncholaimus, Dujardin ; ? Odontohius, 

 Eoussel ; Diplogaster, M. Schultze ; ? Dorylaimus, Dujardin ; ? 

 Phanoglene, j^ordmann ; Dicelis, Dujardin ; ? Phacelura, Hemprich 

 and Ehrenberg ; Leptodera, Dujardin ; Pontonema, Diesing ; Isacis, 

 Lespes ; ? Nema, Leidy ; ? Hemipsilus, Quatrefages ; ? Fotamonema, 

 Leidy. 



Oordiidce. — The filiform, thread-like hair-worms are for the 

 most part characterised by the possession of an extremely elon- 

 gated body, which is usually supphed with a mouth and intestinal 

 canal, the latter ending coecally instead of opening by an anus. In 

 Gordius aquaticus there is a mouth and oesophagus but no intestine, 

 a similar rudimentary condition of the digestive apparatus being 

 also found in Mermis nigrescens. In Anguillina monolis — which I 

 take to be identical with the Filaria rigida infesting different 

 species of Aphodius — the intestine is, according to Siebold, altoge- 

 ther wanting, and the same may be said of Sj)hcerularia hombi. In 

 the young of Dracunculus, as recently shown by Mr. Bastian, the 



