Parasitic in the intestine, more especially the stomach, of mammals (twenty species), birds (twelve species), reptiles (fourteen species).
Physaloptera caucasica, v. Linstow, 1902.
The male measures 14·2 mm. in length and 0·71 mm. in breadth; the bursa is broad, rounded off in front and narrower at the back; the right spicule measures 0·62 mm. in length, the left spicule 1·76 mm.; there are two papillæ in front of the orifice of the cloaca, four behind it and six unpedunculated on the tail. The female measures 27 mm. in length, 1·14 mm. in breadth; the caudal extremity is rounded off; the vulva is on the border of the first and second sixth of the length of the body; the eggs have thick shells, and measure 57 µ by 39 µ. It has hitherto only been observed once, by Ménétriés in the intestine of man (Caucasus).
Fig. 339.—Bursa of Syngamus trachealis. a., anterior ray cleft; a.e., antero-external; m.a., antero-median; m.l., postero-median; p.e., postero-external; p., one branch of posterior (trifurcate). (Stephens.)
Physaloptera mordens, Leiper, 1907.
Large worms resembling an immature Ascaris lumbricoides.
The inner lancet-shaped teeth have a sharp cutting edge towards the lumen. Below each is a cuticular boss projecting into the mouth (fig. 340).