OXYURINAE 21 



Fam. 5. OXYURIDAE Cobbold, 1864. 



Parasitic forms. Meromyarian. Mouth with simple, 

 usually inconspicuous lips. No buccal capsule. Oesophagus 

 usually with a pharynx and always with a distinct posterior 

 bulb, containing three valves. Reproductive organs simple. 

 Oviparous. Ovaries short, producing relatively few large eggs. 

 Excretory pore at about the level of the oesophageal bulb or 

 even behind it. Caudal end of mature female always elongated 

 and subulate. Male without a preanal sucker, except in 

 Hoplodontophor us . 



This family appears to form a fairly homogeneous group, 

 and we have not felt justified in retaining the families Pharyn- 

 godonidae and Isakidae of Travassos (1920 ( ?)). The con- 

 tents of the former appear to fall naturally into the subfamily 

 Oxyurinae, while Isakis, the sole representative of the Isa- 

 kidae, may be included among the Cosmocercinae. The 

 subfamily Syphaciinae Railliet (1916, Rec. Med. Vet., 521) 

 is discarded, since its genera also appear to fall into the 

 Oxyurinae. 



Subfam. 1. OXYURINAE Hall, 1916. 



Mouth with three or six lips. Male with a single spicule, 

 which may be vestigial (rarely without a spicule), and usually 

 without an accessory piece. The caudal papillae of the male 

 mainly in the vicinity of the cloaca. 



1. Oxyuris Rudolphi, 1803. 



Syn. Lepiuris Schlotthauber, 1860. 



Lips not apparent. Cuticle of head not inflated. Mouth 

 hexagonal. One pair of lateral and two pairs of large sub- 

 median cephalic papillae present. Oesophagus relatively 

 short, hourglass-shaped, with a short pharynx, containing 

 numerous cuticular bristles in both sexes and three prominent 

 teeth in the female. Its narrow middle portion passes 

 gradually into the posterior pyriform bulb. Tail of male 

 truncate, with alar expansions in front of and behind the 

 cloaca, each supported by a pair of pedunculate papillae. 

 Two pairs of smaller caudal papillae present. A single spicule, 

 without an accessory piece. Tail of female extremely lone. 

 Vulva towards the anterior end of the body, but postoesoph- 

 ageal. The common trunk of the uterus extremely long, 

 extending almost to the posterior end, and there dividing 

 into two short branches which run parallel to each other in 

 the anterior direction. Eggs elongated, flattened on one side, 

 unsegmented when laid, with thick shell, having an opening 

 at one pole filled by a plug which is outwardly concave. 



