NO. 1-33. LANCELETS, etc., FROM JAPAN— JORDAN AND SNYDER. 733 



and never tvieuspid. SnuiU lampreys inlia))itino- the brooks of Europe, 

 Asia, and North Ameriea. 

 a. Dorsal tin divided into two parts, separate or joined at l)ase only; intraoral 



lamina with 6 to 8 sharp cusps joj^nwd, 4 



aa. Dorsal fin distinctly continuous, but with a sharp notch; infraoral lamina with 



6 to 7 blunt cusps mitsuknrli, 5 



4. LAMPETRA JAPONICA i Von Martens). 

 YATSLTMEUNAGI (EIGHT-EYED EEL). 



PetfoviyzonjaponicusMARTEyis, Archiv. Naturg.. XXXIV, 1868, p. 3; Japan. 



Pdwmyzon fuviatUis Ishikawa, Prel. Cat., 1897, p. 63, Yamagata, Xiigata, 

 Takata, R. Shimigu, Totomi, Owari, Kioto, Uji in Yamashiro, Lake Biwa at 

 Xagahama in Omi, Hatta, Lampreys of Japan. Rivers of southern Hondo. 

 (Xot of Linnfeus. ) 



Siipraoral lamina formino- a long, crescentic plate, with a sharp 

 cusp at either end; no median cusp; infraoral lamina with seven (six 

 to eioht) sharp cusps, which are nearly equal, except that the outer is 

 much broader than the others; lateral teeth, three on each side, each 

 with tw-o c-usps; tong-ue with nine cusps, the median nmch the larg- 

 est; lips fringed; tw^o rows of simple teeth in front of mouth above. 

 Dorsal tins entirely separate, the first not quite half the height of the 

 second, the interspace '21 in head; 2i in length of first dorsal. Gill 

 openinus, 7; head, lyV in thorax; snout. If in head; head, lU in total 

 length; greatest depth, If in head. Tail, 4i in total length. Blackish; 

 paler below; tail darker; dorsals edged with pale. 



Rivers of southern Hondo, north al)out to Niigata and 8endai, gen- 

 erally common. Here described from a specimen 18i inches long 

 froni Shinano River in Echigo. Other specimens obtained by us are 

 from near Tokio (infraoral cusps six. the outer more enlarged); one 

 from Noyshiro. six cusps; Noyshiro. eight cusps, the two outer coal- 

 escent on either side. 



This species is very close to Lanipetra aurcd (Bean), of the Yukon 

 River, and to Lmipetra jimkitilk Linnteus, of the streams of Europe. 

 Our material is not sufficient to show that it is really different from 

 either or both of these. It is, however, very undesirable to tmite 

 nominal species from widely separated regions lintil identity is actu- 

 ally shown. This species seems to have a higher second dorsal than 

 the European species. From Dr. Hatta"s map of the distri])ution of 

 lampreys in Japan, it is evident that the present species has a much 

 more southerly range than the other. This would indicate that it is 

 not identical with the lamprey of the Yukon. The species is known 

 in Japan as Y'atsumeunagi, or Eight-eyed Eel. 



Lampvtra ermtii (Dybowski) (Fischfauna des Anmrgebietes, 187'2, 

 2l>(»), from the mouth of the Amur, is also close to Lainpetra japun- 

 iea, but is said to have 19 denticles in a row acros.s the tongue. 



