NEMATODE PARASITES OF BIRDS 345 



ovaries, oviducts, and uteri. Anus 71/x from the end of the tail. 

 The vulva is 310ju from the end of the tail. It connects with a very 

 short vestibule (fig. 409 a, b, and c) which presents on its ventral 

 surface a diverticulum closed at its free end, 400/* long, its walls 

 having the same structure as that of the vestibule. This is not a 

 receptaculum seminale but a " copulatory bursa " or copulatory re- 

 ceptaculum, analogous to that of various insects, having a role in 

 copulation, such as the role played by the vestibule of other nematode 

 parasites. Sphincter very short, continued by a trompe, which soon 

 divides into two branches which join the uteri. The uteri measure 

 21 and 19 mm., respectively, thus are 6 times the total length of the 

 body; the distal extremity, connected with the oviduct, is enlarged 

 into an ampoule and differentiated as a receptacle seminale. Oviduct 

 and ovary represented by a slender tube 6 mm. long. Eggs 48 to 56/x 

 long by 26 to 30/x wide and containing well developed embryos when 

 deposited. 



Larva, fourth stage, 1.65 mm. long, straight and slender (female) ; 

 tail (fig. 409d) long with rounded tip bearing 8 ( ?5) long spines 

 (Seurat says 8 and figures 5) and with 2 latero-ventral spines 70 p 

 posterior to the anus. 



Life history. — The eggs pass out in the feces and are swallowed 

 by so-called " water fleas " (Daphnia pulex) or " sand fleas " {Gam- 

 marun pulex) under favorable conditions. In these hosts the larvae 

 develop to the infective stage in the body cavity, and when such hosts 

 are swallowed by suitable birds in feeding or drinking, the worms 

 become mature, mate, and the females then enter the canals of the 

 glands of Lieberkuehn, the males remaining in the lumen of the 

 proventriculus. The female lies with the tail in the duct and the 

 head in the fundus, to facilitate the passage of eggs and feeding. 

 The body becomes distended with eggs. Travassos has compared this 

 habit of life with that of the chigoe flea, and the tetramere may well 

 be regarded as a sort of entoparasitic, verminous chigoe. 



Distribution. — North America (United States), Oceania (Guam), 

 Asia (Russian Turkestan and Philippines), Europe, and Africa 

 (Algeria). The North American reports probably deal largely, if 

 not wholly, with T. americana (see p. 337). 



TETRAMERES GIGAS Travassos. 1919b 



Synonym. — Tetrameres inflata of Zuern, 1882, not Diesing, 1861, 

 of Travassos. 



Hosts. — Primary: Anas boschas domestica; secondary: Unknown, 

 probably similar in a general way to that of T. fissispina (p. 343). 



Location. — Glandular stomach or proventriculus. 



Morphology. — Tetrameres (p. 334). 



