The genus isolaimium cobb, 1920 (order isolaimida, isolaimiidae new family).

Five species of lsolaimium Cobb, 1920 are described and illustrated: I. nigeriense n. sp., I. multipapillatum n. sp., I. caliIornicum, n. sp., I. papillatum Cobb, 1920, and I stictochroum Timm, 1961. A unique feature in lsolaimium, not found in any other nematode, is the presence of six cuticularized tubes surrounding the stoma and opening on the head. Order Isolaimida Cobb, 1920 is emended to accommodate this genus, which is considered to lie between the mermithoids and the dorylaimoids.