NEMATODE PARASITES OF BIRDS 355 



MICROTETRAMERES HELIX, new species 



Host. — Primary : Corvus americanus; secondary : Unknown ; prob- 

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



Location. — Proventriculus. 



Morphology. — Microtetrameres (p. 351). 



Male 4.9 mm. long by 100/n wide. There are no longitudinal rows 

 of spines on the body. Buccal capsule 21/* deep; pharynx 274/*, 

 long; esophagus 531/t long. Nerve ring 191/*, from anterior ex- 

 tremity. Tail (fig. 417a) slender; cloacal aperture 183/* from pos- 

 terior end ; cloacal lips prominent. Two small preanal and two small 

 postanal papillae in the ventral line. Two very unequal spicules, 

 the longer 3.6 mm. long, extending almost to esophageal region; 

 distally it ends in two sharp points. Shorter spicule 135/x long, 

 very feebly chitinized and therefore difficult to see; its distal end 

 rounded. 



Female, when coiled, 1.2 to 1.3 mm. long by 1 to 1.3 mm. wide. 

 Body loosely coiled; starting from the head end there are approxi- 

 mately one and one-half turns or coils in one direction, the direction 

 then reverses itself for approximately one turn (fig. 417 o and c). 

 No longitudinal furrows as in Tetrameres. Cuticle very loose, pro- 

 jecting from the body in transparent folds. Head end blunt; buccal 

 capsule 22.5/* deep; pharynx 225 to 250/* long; esophagus very 

 thick, soon becoming obscured by the uterine coils so that its distal 

 end is not observable. Anus 141/*, vulva 216/* from posterior end, 

 which is finely pointed and projects out from a transparent cuticular 

 collar (fig. 417 d). Eggs 42/* long by 33/* wide; embryonated. 



Life history. — Probably similar in a general way to that of T. 

 -fissispina (p. 343). 



Distribution. — North America (United States (District of 

 Columbia) ). 



Type material. — No. 2064 U.S.N.M. (Bureau of Animal Industry 

 helminthological collection). 



MICROTETRAMERES INERMIS (Linstow, 1879) Travassos, 1915b 



Synonyms. — Tropidocerca inermis Linstow, 1879«; Tetrameres 

 inermis (Linstow, 1879) Travassos, 1914ri. 



Hosts. — Primary: Astur nisus, Astur palumbarius, Corvus corax 

 tingitanus, Passer domesticus, Corvus frugilegus, Corvus corone, 

 Lanius, species, and sparrow-hawk (Epervier) ; secondary: Un- 

 known; probably similar in a general way to that of T. -fissispina 

 (p. 343). 



Location. — Proventriculus. 



Morphology. — Microtetrameres (p. 351). 



