2 PROCEEDINGS OF THE NATIONAL MUSEUM vol.68 



median lobes are broadly rounded. Each lobe has on its inner sur- 

 face an anteriorly projecting plate, the free edge of which is 

 dentate, that of the median lobe having a large central tooth and 

 at each side 4 or 5 smaller teeth; that of the lateral lobes 3 teeth 

 at each side of the large central one. The lobes of each lip appear 

 quite disci'eet, there being considerable space between them; they 

 have a heavy chitinous lining. Four submedian papillae present. 

 Mouth opening oval, elongate dorso-vent rally ; pharynx large, cylin- 

 drical, its diameter increasing somewhat posteriorly. Nerve ring 

 surrounding esophagus near its anterior end; cervical papillae very 

 small, located in depressions of the cuticle at the level of the nerve 

 ring; excretory jjore a short distance posterior to the nerve ring. 



Male.— Tot'dl length 22 to 43 mm.; width QOOfi to 1.2 mm. In 

 a specimen of medium size the Avidth of the head at base of lips is 

 160 to 165/x; the lips are 50/a long, the median lobe 58/i, wide; width 

 of body at posterior end of esophagus 500/x, at the curve of the 

 caudal end 500/u,, at the level of the cloacal aperture 350,u. Pharynx 

 150 to 160/x long by 60 to TiV wide; esophagus 4.2 mm. long (^ of 

 total body length) by 300/a in maximum width; nerve ring 200/1 

 from anterior end of esophagus. Posterior end of body tightly 

 coiled. Tail short, the cloacal aperture -^^ of total body length 

 from posterior end. Two caudal alae of approximately equal size, 

 measuring 1.4 nun. long in large specimens; the maximum width 

 of 265/* attained at about the middle of their length; they have 

 fine wavy transverse striations and their outer edge is irregular. Ven- 

 tral surface of body for a distance of 5.5 to 6 mm. anterior to caudal 

 end provided with vesicular swelling of cuticle. As seen from the 

 ventral surface, with the cover glass compressing the vesicular in- 

 flation of the cuticle laterally, the caudal alae are completely hidden 

 from view, lying dorsal to this inflation. The latter is covered with 

 rounded oblong markings of varying size, similar to those found 

 in other species of the genus. In addition to the oblong markings, 

 and correlated with them, are brilliantly refringent dots, confimcl to 

 the ventral region and the posterior half of tlie vesicular inflation, 

 gradually disappearing laterally and anteriorly. These dots are 

 not superficial, as are the markings, but lie just below the surface. 

 Not only the circumcloacal region but also the median ventral sur- 

 face of the body from the cloacal aperture to the tail end is de- 

 void of both the oblong markings and the dots. Six pairs of long 

 jjedunculated papillae, of which four pair;- are preanal and two 

 pairs postanal; in addition there are five pairs of very small sessile 

 papillae at the caudal extremity, which are not apparent except in 

 a direct ventral view of the tail. Spicules slightly unequal, the one 

 1.3 to 1.4 mm. long by 33 to 37/i wide, with distal end rounded ; the 

 other 1.03 to 1.07 mm. long by 18/x wide, with distal end sharply 



