COELHELMINTHES 227 



Family ]\Ietastrongylidse, Leiper, 1908. 

 ''Buccal capsule absent. ]Male with two equal spicules and female 

 with two ovaries. Eggs in van-ing stages of development when ovipos- 

 ited. Embiyo not rhabditiform. Parasitic in the respiratory and cir- 

 culator}' systems. 



Subfamih' Metastrongj-linte, Leiper, 1908. 

 T3'pe-genus Metastrongylus, Molin, 1861. 

 "Body usually very long and slender. Mouth with two lips or with- 

 out lips and surrounded with circumoral papilla?. Esophagus slender, 

 without posterior bulb. Anus subterminal. INIale with a single spicule 

 or with two unequal spicules. Tail provided with papillae, usuall}^ 

 curved spirally, and with bursal alse present or absent. Female larger 

 than male. Vulva present, or, less often, absent in gravid females; 

 when present, usually anterior to the middle of the body or near the 

 middle, rarely near posterior extremity. Oviparous, ovoviviparous, 

 or viviparous. Development in many cases, perhaps in all, requires 

 an intermediate host. 



Superfamily Filarioidea, Weinland, 1858. 

 ''Body long and filiform. Alouth without lips. Male with two 

 spicules, usually quite dissimilar. Vulva near the anterior extremity of 

 the body. Adults subcutaneous, in blood, or on serous surfaces. 



Tj^pe-family Filariidse, Claus, 1885. 

 "Vulva anterior, near mouth. Spicules quite dissimilar. Inter- 

 mediate stages, so far as known, occur in blood-sucking arthropoda. 



Subfamily Filariina?, Stiles, 1907, 



Type-genus Filaria, Mueller, 1787, 



"Mouth with two lips; or without lips in forms where vulva is near 



posterior extremit}' of body, Male with posterior extremity of body 



commonly expanded and alate. Female with \'nlva usually in middle 



portion of body, exceptionally near posterior extremit}^ 



Family Spiruridae, (Erly, 1885. 

 Type-genus Spirura, E. Blanchard, 1849. 

 "Bod}' long and filiform. Anterior portion of bod}' ornamented with 

 cuticular bosses. In the median lines, immediately behind the mouth, 

 are two semilunar depressions sinmlating suckers. The vulva is sit- 

 uated a short distance anterior of the anus. 



Subfamily Gongyloneminse, Hall, 1916. 

 Type-genus Gongylonema, Mohn, 1857. 

 "Females with two uteri and with \ailva in the middle portion of 

 the body, not close to anterior or posterior extremities. Pharjmx with- 

 out cuticular rays or spirals. 



Subfamily Spirurinae, Railliet, 1915, 



Type-genus Spirura. E. Blanchard, 1849. 



"INIouth with two lips leading into a pharynx which is strengthened 



