FREE-LIVING NEMATODES 



4og 



56 (51) Caudal glands and cephalic setae absent 



. . Alaimus de Man. 

 The species of this small kciius have a 

 rather simple structure. All are slender. 

 Some appear to be parthenoKeiictic. 

 Representative species. 



Alaimus simplex Cobb 19 14. 



r . I?.. . "■ r- " »■«• 92 



I. .J .e'^"':9 i i 6 ' ■■ 



r . ;2. . 7. _ 1$ M 94 



Very minute striations in subcuticula at 

 extremities, under favorable conditions. 

 Obscure traces of lateral winRs. Krks ap- 

 parently deposited before segmentation be- 

 gins. Whether two testes or only one not 

 determined. Broad, nninded, blunt end of 

 testis, located as far behind base of neck as 

 latter is behind anterior extremity. 



Habitat: Big Lake, Fla. 



Fig. 803. Alaimus simplex. 



I, lateral view of a female; II, anterior ex- 

 tremity, lateral view; III, posterior extremity 

 of a male, lateral view. 



a, lip region; b, phar>'nx; c, amphid; d, 

 amphid, enlarged; e, group of spermatozoa at 

 posterior portion of ovarj- ;/, blind cnfl of ovary; 

 g, male supplementary paijillae; h. left spicu- 

 lum; i. terminus; 7, submedian elevation or flap 

 indicating rudimentary bursa; k, egg; /. vulva; 

 w, nerve-ring; «, posterior extremity of esopha- 

 gus; p, modified cells of anterior intestine; (j, 

 cuticula; r, wall; 5, lumen of intestine; /, flexure 

 in single ovary. (After Cobb.) 



57 (50) Pharynx present 58 



58 (59) Pharyngeal cavity relatively large, amphids very small if any. 



Prismatoldimus de Man. 



Well-characterized genus consisting at present of four 

 or five species. This genus resembles Monhystera to a 

 certain extent. 

 Representative species. 



Prismatolaimus stenurus Cobb 1914. 



£= 



Behind each amphid, at a distance equal to the width 

 of two to three annules of the cuticula, there is a short 

 seta. The ovaries are moved backward and forward 

 in accordance with stage of development of eggs. These 

 latter appear to be deposited before segmentation begms. 

 Notwithstanding the slenderness of the tail caudal glands 

 and a spinneret are present. 



Habitat: Roadside pool, Douglas Lake, Michigan. 



Fig. 804. Prismatolaimus stenurus. 



side 



I, lateral view of a female; II. front view of head: III, 



Tone'ofthe six cephalic papillae; 6, one of the ten ccphalk 

 setae; c, one of the six thm lips; d, pharynx; e ^mph 1 /. 

 lumen of the esophagus;..^- nerve-nng; h cu .cula; •• n"-;''^ 

 of ovum; j, vulva; ^, bhnd end of l>«Jt«-"r'«^,^."^;'^J ; '■ ^ ^ 

 beginning of the intestine; n. one of the cells of the ^^i'"' -;'/f«^ 

 Einef ., rectum; />• ^""^^'Z' «"^ "^^i7,^■:'Sl^l3t"^*'• '' 

 flexure in anterior ovary; 5, spinneret. (After Lobb.) 



