66o 



NEMA THELMINTHES 



TriodontophorusLooss, 1901. 



Synonyms— Trio dontus Looss, 1901, nec Westwood, 1845; Terni- 

 dens Railliet and Henry, 1909. 



Strongylidae with small, almost spherical, thick-walled oral 

 cavity, arising from the floor of which three teeth are found, each 

 of which consists of two surfaces joined together at an acute angle. 

 Male bursa is finely serrated at the edge. The female genital orifice 

 is situate a short distance in front of the tip of the tail. 



Found in horses and men. 



Triodontophorus deminutus Railliet and Henry, 1905. 



Synonym,— Ternidens deminutus (Railliet and Henry, 1905). 



Railliet and Henry in 1905 discovered that a male and female 

 parasite presented in 1865 by Monestier to the Paris Natural 

 History Museum, and collected post-mortem from an American 

 negro who died in Mayotte, were not ankylostomes, but belonged 

 to Looss's genus Triodontophorus. They named them deminutus 

 because of their small size. Leiper also met with some specimens 

 of the same species collected in Nyassaland and Lorengo Marques. 

 It has now been recorded in a number of cases. It is also found in 

 monkeys. Their normal habitat is the large intestine. 



Morphology. — To the naked eye their size and general appearance resemble 

 those of ankylostomes. The body is white, cylindrical, tapering towards 

 the end. Cuticle transversely striated, and forms an overhanging transverse 

 fold across the ventral surface of the body at the level of the excretory pore. 



The mouth-collar is moderately developed, with a depth of 0*04 millimetre. 

 The anterior surface carries four small knob-like submedian papillae, and the 

 edge surrounds the entrance to the mouth with a double series of delicate 

 fringes composed of cuticle. These two rows constitute the external and 

 internal crowns of the corona radiata. 



The buccal capsule is a barrel-shaped chitinous structure, capped and 

 covered in by the mouth-collar and the corona radiata. Posteriorly it touches 

 the dilated end of the oesophagus, whose chitinous lining expands into a 

 funnel, uniting with the cuticle on the outside of the oesophagus, and coming 

 near the cuticle of the buccal cavity. It shows three cuticular edges project- 

 ing into the lumen, which are continued forwards as three stout chitinous 

 prongs or teeth, one dorsal and two ventral. The characters of these teeth 

 are specifically important. They are formed of two plates curved longi- 

 tudinally, and meet to form a keel. The oesophagus is muscular, o*8 milli- 

 metre long, with three fleshy valves guarding its entrance into the chyle 

 intestine. The rectum is short, and ends in the anus, which is 0*24 millimetre 

 from the tip of the tail. The excretory system opens on the ventral surface 

 halfway between the posterior limit of the buccal cavity and the nerve ring. 



The male is 9*5 millimetres long by 0'56 millimetre in breadth, with a 

 spicule 0-9 millimetre long. Female is 14 to 16 millimetres in length, and 

 0'73 millimetre in breadth, with a tapering posterior extremity. The vulva 

 is nearly 0-48 millimetre from the hinder end. The vagina is short, and opens 

 into two uterine tubules. The uterine eggs are 60 to 80 ^ by 40 ^, with a 

 delicate shell and often a morula. 



Life-History and Pathogenicity. — Unknown. 



