C(ELHELMINTHES 225 



form penetrates to and encysts in the musculature of the host of the 

 adult worm. 



Superfamily Trichinelloidea Hall, 1916. 



Type-family Trichinellidae Stiles and Crane, 1910. 



"Male without spicule. Female ovoviviparous; the spherical egg is 



surrounded with a delicate membrane abd is without a true eggshell. 



Worms in the intestine of the host animal. 



Subfamily Trichinellinae Ransom, 1911. 

 Type-genus Trichinella Railliet, 1895. 

 "Male with one spicule, or, exceptionally, with only a copulatory 

 sheath. Eggs lemon-shaped, the apertures at each end closed with 

 opercular plugs. Development, so far as known, direct and without 

 intermediate host. Egg development often slow. Eggs with thick shell; 

 do not hatch until swallowed by a suitable host. 



Subfamily Trichurinse, Ransom, 1911. 

 Type-genus Trichuris, Roederer, 1761. 

 "Mouth commonly provided with two or three prominent or incon- 

 spicuous lips which are often supplied with papillse, but the mouth 

 may be of variable shape and without lips. When three lips are present 

 ■one is median and dorsal, the others are submedian and are approximated 

 in the ventral line. Buccal capsule is not present. Males are provided 

 with one or two spicules, rarely with none. Female with two ovaries, 

 oviparous, rarely, as in Oxyuris vivipara, viviparous. As a rule develop- 

 ment is direct and without intermediate host; exceptionally (as in 

 ascarids of fish) there is an intermediate host. 



Superfamily Ascaroidea, Railliet and Henry, 1915. 

 "Mouth with three prominent lips supplied with papillae, the dorsal 

 lip being median and the two other submedian and approximated in 

 the ventral line, or with three main lips and three relatively prominent 

 and inconspicuous intermediate lips (interlabia) . Male usually with 

 two spicules. Caudal extremity of female terminates conically and 

 fairly abruptly. 



Type-family Ascaridae, Cobbold, 1864. 

 Type-genus Ascaris, Linnaeus, 1758. 

 "Mouth provided with two or three lips or without lips and of va- 

 riable shape. Esophagus cylindrical or club-shaped, often followed by 

 a distinct bulb. Males with a preanal sucker, which may be limited 

 by a chitinous ring or a delicate cutaneous membrane, or formed by a 

 simple longitudinal depression; this sucker is not present in Seuratum. 

 Two spicules, one or both of which may tend to atrophy or show im- 

 perfect chitinization, and with accessory piece present or absent. Vulva 

 jiear middle of body. 



Family Heterakidse, Railliet and Henry, 1914. 

 "Mouth with three well-defined lips; esophageal bulb present or 



