found: Hardisty, M.W. Biology of the cyclostomes, 1979.
found: Tandler, G. The Cyclostomata, 1979.
found: Heintz, A. New agnaths from Ringerike sandstone, 1969.
found: Syn. liv. org.:v. 2, p. 830 (Agnatha. Vertebrates without true gillarch jaws. The class is sometimes elevated to the level of a superclass, composed of 1 extant class, the Cephalaspidomorphi (lampreys and hagfishes).)
found: Ox. dict. nat. hist., 1985:p. 14 (Agnatha (Marsipobranchii; phylum Chordata, subphylum Vertebrata). Superclass of jawless, fish-like vertebrates) p. 180 (Cyclostomata. Def. 2: Agnatha, marsipobranchii. The group comprising the most primitive living vertebrates, also called jawless fish. The taxonomic status of the term 'Cyclostomata' is somewhat confused: at various times it has been ranked as order, superorder, subclass, and class.) p. 379 (Marsipobranchii. Alternative name for Cyclostomata (Agnatha))
found: Web. 3(jawless fish: any of the primitive vertebrates comprising the superclass Agnatha)
found: Nelson, J.S. Fishes of the world, c1994:pp. 24-25 (Superclass Agnatha (Cyclostomata, Marsipobranchii); agnathans; cyclostomes)
found: Encyc. of fishes, 1995:p. 24 (Superclass Agnatha - Jawless fishes)
