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BULLETIN 140, UNITED STATES NATIONAL MUSEUM 



Morphology. — Heterakis (p. 50) : The original descriptions of 

 both Ascaris papulosa and Heterakis monticelliana are inadequate; 

 that of H. stylosa is more complete. Baylis has examined speci- 

 mens of both II. monticelliana and H. stylosa and finds them identi- 

 cal. The combined descriptions follow : Cuticle smooth, very thick ; 

 head with 3 anteriorly directed lips; esophagus thin, with bulb at 

 posterior end. Baylis says that, contrary to Stossich's description, 

 narrow lateral alae are present along almost the whole length of the 

 body. 



Male 9 to 13 mm. long by 620/x wide. Esophagus % of total 

 length. Caudal alae (figs. 91 and 92) wide, elliptical. Preanal 



Figs. 89-92. — 89, Heterakis longecaudata. a, Cuticle ; b, male tail. 

 After Linstow, 1879. 90, Heterakis macroura. Male tail. After 

 Linstow, 1883. 91, Heterakis papillosa, Male tail, ventral view. 

 After Linstow, 1907. 92, Heterakis papillosa. Male tail, lateral 

 view. After Stossich, 1892 



sucker very prominent, 220/x, large. Baylis states that the lateral 

 view of tail as figured by Stossich shows admirably the highly char- 

 acteristic shape of the sucker. Tail 1/55 of total length, with styloid 

 appendage 610/* long. Stossich described 7 pairs of caudal papillae 

 but evidently overlooked a pair, as Baylis found 8 pairs as described 

 by Linstow, 1 pair near the sucker, 2 lateral and 1 ventral just 

 anterior to cloacal aperture, and 4 postanal. Spicules equal, 610/x 

 long. 



Female 15 to 20 mm. long. Esophagus 1/9, tail 1/9 of total body 

 length; tail finely pointed. Vulva posterior to middle of body; ac- 

 cording to Stossich, it is at the posterior third ; according to Linstow, 

 it divides the body length in ratio of 28 :17. Posterior to vulva in 

 ventral line 3 or 4 mushroom-shaped cuticular bosses. 



