NEMATODE PARASITES OF BIRDS 333 



Family TETRAMERIDAE Travassos, 1914 



Family diagnosis. — Spiruroidea (p. 162) : Characterized by the 

 sexual dimorphism of the species. Male with filiform body, white, 

 unarmed or armed with spines. Cuticle more or less striated trans- 

 versely. Caudal extremity pointed: usually two unequal spicules. 

 Caudal papillae or spines may be present. Female red ; body greatly 

 enlarged in comparison with that of male, its shape either globular, 

 with the two pointed extremities projecting {Tetrameres), or the 

 long axis of the body coiled in a more or less complex manner (Mi- 

 crotetrameres). Digestive tract consists of mouth aperture with 3 

 small lips, followed by a chitinous mouth capsule, a muscular 

 pharynx, a muscular esophagus and a thin-walled, wide, sac-like in- 

 testine which is usually filled with detritus and ends in a narrow 

 tube opening at the anus. Genital system highly developed, the body 

 cavity largely filled with the numerous coils of the uteri, ovaries, 

 and oviducts. Uteri contain an enormous number of eggs in various 

 stages of development, the embryo being well formed when the egg 

 is deposited. Vulva in posterior part of body, near anus. A saccu- 

 lar diverticulum of the ovejector may be present, called by Seurat a 

 " copulatory bursa " but preferably designated by some term not al- 

 ready used for a male structure, such as " copulatory receptaculum." 



Parasitic in proventriculus of birds, the females in the glands of 

 Lieberkuehn, the males usually free in the lumen. 



Type-genus. — Tetrameres Creplin, 1846. 



KEY TO GENERA OF TETRAMEUIDAE 



Body of female globular or spindle-shape Tetrameres, p. 334. 



Body of female with its long axis spirally coiled Microtetrameres, p. 351. 



I have raised the subgenus Microtetrameres Travassos, 19155 to 

 generic rank and have rewritten the diagnoses for the two genera 

 Tetrameres and Microtetrameres on the basis of the difference in body 

 form of the female. The diagnoses of the subgenera of Travassos, 

 which included with the description of the body form of the female 

 the proportionate length of the spicules and the presence or absence 

 of spines in the lateral fields of the male, did not furnish a suitable 

 basis for the division of Tetrameres {sensu lato), at least in the 

 present state of knowledge. T. cruzi, the type-species of the sub- 

 genus Microtetrameres was not consistent with the subgeneric diag- 

 nosis as given by Travassos, as the long spicule of the male is not 

 % the body length, but just slightly over half. In four species 

 the male is unknown; several other species possess certain characters 

 which are included in the description of one subgenus but at the same 

 time possess certain other characters which belong to the other sub- 



