26 VERTEBRATE ANIMALS OF THE UNITED STATES 



3. Petromyzon L. Marine and fresh water lampreys with 2 sepa- 

 rated dorsal fins: several species, i in the United States. 



P. marinns'L. Lamprey eel; great sea lamprey (Fig. 11). Length 

 up to 1,000 mm.; color blackish, more or less mottled; buccal funnel 

 large, with strong, pointed teeth, the innermost lateral teeth being 

 enlarged and usually bicuspid; supraoral lamina with 2 approxi- 

 mated cusps; infraoral lamina with 7 to 9 strong cusps; muscle segments 

 between gills and anus about 70: North Atlantic along the American, 

 European and African coasts; southward to Florida, ascending the 

 streams to breed; common in the interior lakes of New York and 

 Lake Ontario. 



Fig. II. — Petromyzon marinus {from Jordan's Guide to the Study of Fishes). 



4. Entosphenus Gill. Marine and fresh water lampreys with 2 

 separate dorsal fins; teeth in groups, there being a marginal series 

 bordering the edge of the buccal disc, several enlarged teeth on each 

 lateral border of the mouth, a group on the anterior and one on the 

 posterior part of the disc: 3 species, i in Mexico. 



E. tridentatiis (Gairdner). Length 450 mm. or more; color dark 

 brown; 4 enlarged lateral teeth on a side, the first and last bicuspid, the 

 middle two tricuspid; infraoral lamina with 4 to 6 cusps; supraoral 

 lamina tricuspid : Pacific Ocean, from Unalaska to southern California, 

 ascending the streams, in the Columbia as far as Walla Walla. 



E. ciliatus (Ayres). Muscle segments between gills and anus 57 to 

 67: streams of northern California. 



5. Lethenteron Creaser and Hubbs. Similar to Entosphenus: 

 I species. 



L. appendix (DeKay) (£. wilderi Jordan & Evermann) (Fig. 12). 

 Length 200 mm.; color bluish black; enlarged lateral teeth 3 on a side, 

 all bicuspid; infraoral lamina with 8 to 11 cusps; supraoral lamina 

 bicuspid; muscle segments between gills and anus 67 to 73; intestine 

 of adult degenerate: in streams from southern New England to Mary- 

 land; westward to Wisconsin and Iowa; northward into Canada; in 

 eastern Asia. 



