PARASITIC ROUNDWORMS 



525 



24 (23) Only two small conical papillae near mouth. 



Filaria physalura Bremser 181 1. 



Living worm pink with brown intestine and white uteri prominent. Female 30 to 45 cm. 

 long, I to i.s mm. broad. Head obtuse. Mouth with two small conical papillae. Male 

 35 mm. long, 0.615 mm. broad; tail curved with short quinquecostate alae which are 0.35 

 mm. long. Spicule recurved. 



In abdomen of kingfisher; Pennsylvania. "Determination not positive" (Leidy). 



25 (20) Anterior end provided with two lips. Each lip carries two blunt 



hooks. . Filaria cingula von Linstow 1902. 



Length 13 to 25 cm., diameter 0.53 mm. Anterior end bluntly rounded; dorsal and ventral, 

 triangular lips with two blunt hooks in each. Cuticula embossed with low, rounded trans- 

 verse ridges on dorsal and ventral surfaces. Pharynx narrow, 0.375 mm. long, with bulbous 

 enlargement at end. Esophagus triangular, 15 by 0.13 mm. Lateral fields broad. Two 

 ovaries. Vulva? Embryos 0.33 by 0.014 mm. Viviparous. 



In skin of Crypiobranchus allegheniensis; Ohio river. Identification with von I-instow'B 

 meager description uncertain. 



Fig. 818. Filaria cingula. Optical section of the two anterior millimeters; I, lips; p, pharyngeal bulb; 

 0, ovary; e, esophagus; «, uterus; h, hooks; r, ridges. Magnified about so. (After Krecker.) 



26 (17) Esophagus with two separate regions, more or less differentiated. 



Superfamily Spirxjroidea Railliet and Henry 1915 . . 27 



The mouth has two lips, or is without any. Esophagus with partition dividing it into two 

 regions which may be differentiated as anterior muscular and posterior granular region, and 

 may be much alike in appearance. 



Male with lateral alae near posterior end of body. Alae in general long, not much if any 

 wider than body, without ribs or radiate, branching supports. 



Most of these forms were previously included with the Filarioidea from which they are most 

 easily distinguished by the double esophagus. 



27 (42) Anterior end simple, without prominent lateral valve-like lips. . 28 



28 (41) Tail in female simple, not modified in the form of a sucker-like 



structure. ... 29 



29 (40) Male with preanal papillae and without ventral ridges 30 



30 (37) Preanal papiUae in male single not stalked and paired, also few in 



number. . . Family Spiruridae Oerley 1885 . . 31 



There are several subfamilies which contain numerous parasites of terrestrial hosts. 



31 (34) Anterior end plain, unornamented by external ridges or frills. 



Subfamily Spirurinae Railliet 191 5 . . 32 



The mouth has two small lips, or none. The pharynx is simple or wanting. The vulva is 

 at the center of the body, or anterior. 



