NEMATODE PARASITES OF BIRDS 



33 



tral and closed by 6 striated membranous expansions or lips. Buccal 

 capsule well developed, with C meridial ribs in its wall and with a 

 dozen small teeth at its base, two of these, somewhat larger than the 

 others, at the base of the dorsal gutter. 



Male 11 to 18 mm. long. Branches of dorsal ray of bursa (fig. 34) 

 tridigitate, one of the subordinate branches often very slender. 

 Spicules slender, 900/a to 1.025 mm. long. 



Female 17 to 21 mm. long. Vulva (fig. 35) close to the anus and 

 often covered by a cuticnlar expansion. Eggs thin-shelled, 120 to 

 125//. by TO to 75/t, segmenting when deposited. 



Life history. — Unknown; probably simple and direct. 



Distribution. — South America (Brazil) and Europe (in museum 

 material). 



Figs. 33-35. — DelhtrcxXephamjs dimidiates. 33, Head ; a, lateral; b, front 

 view. 34, Male BURSA. 35, Female tail. After Diesing, 1857 



Family SYNGAMIDAE Leiper, 1912 



Family diagnosis. — Strongyloidea (p. 29) : Worms permanently 

 joined in copula (Syngamws) or not permanently joined (Cyathos- 

 toma). Buccal capsule large, thick-walled and armed at the base 

 with 6 to 9 teeth of 2 distinct sizes arranged about a center. Bursa 

 membrane thick or of thickness usual in strongyles in other families; 

 rays often short and thick, sometimes slender. Spicules short (Synga- 

 mus) or long (Cyathostoma). Vulva usually in anterior half of 

 body, rarely median or slightly postme.dian. Eggs operculated after 

 deposition. 



Type genus. — Syngamus von Siebold, 1836. 



KEV TO GENERA OF SYNGAMIDAE 



1. Worms permanently joined In copula. Buccal capsule usually with 8 or 9 

 teeth rarely 3 (error?). Bursa rays short and thick. Spicules small. 



150^ or less. Vulva in anterior half of body Syngamus, p. 34. 



Worms not permanently joined In copula. Buccal capsule with (5 or 7 teeth 

 rarely 2 (error'.'). Bursa rays slender. Spicules Long, over 40Qp. Vulva 

 anterior, median or slightly posterior Cyathostoma, p. 41. 



