FREE-LIVING NEMATODES 



52(55) Amphids spiral. 



497 

 53 



S3 (54) Male supplementary organs papillate Bastiana de Man. 



Named in honor of the English nematologist Henry Charlton Bastian, 1837-1914. 



Genus of slender nematodes with rather simple mouth parts. Males with a ventral row of 

 small supplementary organs extending over the greater part of the length of the body. Half 

 a dozen species known. Occurs in Europe, America, Japan, and AustraUa. 



Representative species Bastiana exilis Cobb 1914. 



The moderately thick layers of the 

 transparent, colorless, naked cuticula 

 are traversed by about eight hundred 

 transverse striae, which do not appear 

 to be further resolvable. These striae 

 exist in the outer as well as the inner 

 cuticula, so that the entire contour of the 

 body is crenate. Rather conspicuous 

 lateral wings are present, the optical 

 expression of which is two distinctly re- 

 fractive longitudinal lines opposite the 

 lateral fields, separated from each other 

 by a distance somewhat greater than the 

 width of one of the annules of the cuticula. 

 There is a circlet of at least six cephalic 

 setae, of which the four submedian are 

 the longer, and are somewhat longer than 

 the head is wide. Possibly each of these 

 latter is accompanied by a shorter seta, 

 thus making ten in all. Apparently 

 labial papillae are present, but they have 

 not been sufficiently clearly seen to per- 

 mit of enumeration. From the rather 

 raised anus the conspicuous rectum, 

 which is twice as long as the anal body 

 diameter, extends inward and forward. 

 The tail is conoidj but tapers more rapidly 

 near the acute terminus. Nothing is 

 known concerning the renette. 



Habitat: Fresh water, Tynne Station, 

 Fla. 



Fig. 800. Bastiana exilis. 



Lateral view of a male specimen. 



a, one of the six cephalic papillae; b, one of the 

 posterior set of four submedian cephalic setae; 

 c, one of the anterior set of six cephalic setae; d, 

 esophagus; e, cervical seta; /, amphid; g, one of 

 the cells of the intestine; h, one of the numerous 

 male supplementary organs; i, blind end of the 

 two testes; the two testes join each other at n, the 

 complete development of the spermatozoa tak- 

 ing place between the locations indicated by * 

 and »; the junction of the testes with the vas 

 deferens is on the far side of the body and is 

 not shown; j, nerve-ring; k, posterior extrem- 

 ity of esophagus (pseudo-bulb); /.left spicu- 

 lum; w, cuticula; «, spermatozoon; o, anal mus- 

 cle; p, terminus; g, vas deferens; f, intestine. 

 rAfter Cobb.) 



