Benthic species of Dorylaimus Dujardin 1845 (Nematoda: Dorylaimidae) and Arctidorylaimus n. gen. (Arctidorylaimidae n. fam.) from the Mackenzie and Porcupine River systems, Northwest Territories, Canada. Canadian Journal of Zoology, 57(4) 1979: 743-755. 743 [Zoological Record Volume 116]