184 CYCLOSTOMATA. 
Sub-class III. CYCLOSTOMATA.. 
Order I. HYPEROARTII. 
Fam. 1. PETROMYZONID. 
Lampreys, with naked eel-shaped body, suctorial mouth, and seven gill-openings on 
each side. 
1. LAMPETRA, Gray, 1851. 
Lampetra, Jord. & Everm. Bull. U.S. Nat. Mus. xlvii. 1896, p. 12. 
Five or six species, small Lampreys inhabiting brooks in Europe and North 
America. | 
1. Lampetra spadicea. 
Lampeira spadicea, Bean, Proc. U.S. Nat. Mus. 1887, p. 374°; Jord. & Everm. Bull. U.S. Nat. 
Mus. xlvii. 1896, p. 13, and 1900, fig. 6°; Meek, Publ. Columbian Mus., Zool. v. 1904, 
p- 2, fig. 1°. 
Hab. Mexico, Rio Lerma System : 
Guanajuato !?; Lake Chapala ®. 
