RHABDITINAE 35 



7. Monhysterides Baylis & Daubney, 1922. 



Lips apparently six, small. Oesophagus with short, 

 muscular anterior portion and longer, partly glandular, 

 posterior " bulb." Caudal end of male tapering, with five 

 pairs of postanal and four pairs of preanal papillae, the latter 

 being very close together, sub ventral and prominent. Spicules 

 unequal, tubular, the longer blunt, the shorter pointed. No 

 accessory piece. 



Hab. [Alimentary canal of] a Fish. 



Genotjrpe : M. piscicola Baylis & Daubney, 1922. 



BayUs and Daubney, 1922, Mem. hid. Mus., vii, 342. 



8. Leiperenia Khalil, 1922. 



Lips " more than six." Oesophagus proper very short ; the 

 posterior bulb, with its " neck," about three times as long. 

 Tail of male tapering. Four small postanal papillae at about 

 the middle of the tail. Spicules unequal. An accessory 

 piece present. Tail of female long and slender. 



Hab. Alimentary canal of Elephants. 

 Genotjrpe : L. leiperi Khalil, 1922. 



Khalil, 1922, Ann. Mag. Nat. Hist., (9) ix, 215 ; 1922, Proc. 

 Zool. Soc. London, 206. 



Fam. 7. RHABDITIDAE Micoletzky, 1922. 



Small forms, free-living or parasitic, or with both free- 

 living and parasitic phases, with a three-sided, prismatic or 

 tubular buccal cavity, usually without teeth. Oesophagus 

 usually with a posterior bulb containing valves, and frequently 

 also with a prebulbar swelling. Cuticle without bristles, or 

 with very few. Reproductive organs simple. Oviparous or 

 viviparous, not infrequently parthenogenetic or hermaphro- 

 dite. 



This family is divided by Micoletzky (1922, Arch. /. 

 Naturg., Ixxxvii) into four subfamilies (Cylindrolaiminae, 

 Plectinae, Rhabditinae and Bunoneminae). We have been 

 unable to find sufficient characters to separate the Plectinae 

 from the Cylindrolaiminae, and have therefore merged these 

 two groups into a single one. The subfamily Bunoneminae 

 consists of two genera which possess very well-marked and 

 obvious characters. The distinctions between the Rhab- 

 ditinae and Cylindrolaiminae are not felt to be very satis- 

 factory, but these two groups are, for the present, retained. 



Subfam. 1. RHABDITINAE Micoletzky, 1922. 



Buccal cavity elongate, typically a three-sided tube without 

 tooth-like structures. Lateral organs and caudal glands 



