230 



BULLETIN 140, UNITED STATES NATIONAL MUSEUM 



its margin is a pair of papillae. Four cordons originating in pairs 

 between the lips; the 2 cordons of each pair gradually swing to the 

 submedian lines and do not extend beyond the anterior third of the 

 anterior esophagus; they do not recur or anastomose. Cordons 

 double and composed of 2 rows of discrete, sharply pointed elements 

 (fig. 293 a and b) which project like spines; they may extend for a 

 length of 10/30 to 10/41 of that of the anterior esophagus, the average 

 being 10/35. Cuticle with wide transverse striations. Cervical 

 papillae at the level of the union of pharynx and esophagus. 



Male 15 mm. long (14 to 20 mm. in specimens of Stafseth and 

 Kotian) by 183/j, wide at the level of the posterior end of the esopha- 

 gus and 232/jt wide in the middle of the body. Cordons 495^. long. 

 Pharynx or buccal cavity 232ju, long; anterior esophagus 1.1 mm. 

 long; posterior esophagus 2.6 mm. long. Caudal extremity tightly 



Fig. 294. — Cheilospirura spixosa. Male tail. Original. 



coiled. Caudal alae (fig. 294) broad and vesicular; a central band 

 extending lengthwise has delicate transverse striations. Caudal 

 papillae very slender ; 4 pairs of preanal papillae ; 6 pairs of postanal 

 papillae arranged as follows : One group of 2 pairs not far posterior 

 to cloacal aperture, another group of 2 pairs near the caudal ex- 

 tremity, and between these 2 groups the other 2 pairs, the 2 papillae 

 of each pair being asymmetrically placed. Cloacal aperture 498//, 

 from posterior end of body. Spicules unequal and very dissimilar, 

 the one slender, 700 to 720/* long (660/a according to Stafseth and 

 Kotian), the other thick, 192 M long (fig. 293c). 



Female 34 to 38 mm. long (37 to 40 mm. in specimens of Stafseth 

 and Kotian) by 315^ wide at posterior end of esophagus and 348/a 

 wide in middle part of body. Cordons 797 to 813/x long. Pharynx 

 or buccal cavity 232^ long; anterior esophagus 1.4 mm. long; pos- 

 terior esophagus 3.4 mm. long. Vulva (fig. 293c) anterior to middle 

 of body, dividing body length in ratio of 17 : 23. Anus 250 to 300/x 

 from posterior end. Tail (fig. 293^) slender and digitate. Eggs 39 

 to 42/a by 25 to 27/x. 



