Jordati and Ever maun. — Fishes of A'orth A^nen'ca. 1.1 



a. Heail 73.2 ill length; iiifraor;il lamina witli T cusps. concolor 9. 



aa. Hoad 9 in length; iufraoral lamina with 7 to 12 cusps. castankus 10. 



9. ICHTHIOMYZOX CONCOLOR, (Kirtland). 



(Silvery Lamprev.) 



Body considerably compressed ; head broad, with Large buccal disk, 

 which is moderately fringed; teeth strong and nearly uniform, the 2 

 eupraoral teeth being similar to those on the rest of the disk ; lateral 

 teeth all simple; infraoral cusps connivent, 7 in number, the middle ones 

 tlie longest ; upper margin of dorsal scarcely depressed in front of the 

 vent; origin of dorsal nearly midway between the tip of snout and end 

 of tail ; 51 muscular impressions between gill openings and vent. Head 

 11; depth 12. Color, silvery, bluish al)ove, sometimes with bluish spots; 

 a small dusky spot above each gill opening, usually conspicuous even in 

 the larva; larva with small toothless contracted mouth, as in P. marinu8. 

 It may be that this is the young of Petromyzon mariniis. L. 12 inches. 

 Great Lakes and upper Mississippi Valley ; rather common ; ascending 

 small brooks in the spring, (concolor, uniformly colored.) 



Petromyson nrgentens, Kirtland, Bost. Jour. Nat. Hist., iii, 1840, 342, with plato (name pre- 

 occupied), Big Miami River. 

 Ammoccetes concolor, Kirtland, I. c, 473, with plate (larva), Mahoning River ; Scioto River. 

 f Ammocoetes boreali3, Agassiz, Lake Superior, 252, 1850, Michipicoten River. 

 ? Ammoccetes lepi/tcrns, Abbott, Proc. Ac. Nat. Sci. Phila., 1800, :i27 (larva), Ohio River. 

 Petiomyzon hdeUiian, Jordan, Cat. Fish. N. A., 4, 1885, after Kirtland. 

 Pelromtjzon concolor, Jordan k Fordice, Ann. N. Y. Ac. Sci., 188G, 282. 

 IcliOiyomyzon argenlcua, Jordan & Gilbert, Synopsis, 10, 1883. 



10. ICHTHTOMYZON CASTANEUS, Girard. 



Supraoral lamina tricuspid; some of the lateral teeth bicuspid; infra- 

 oral lamina with 7 to 12 cusps ; head 9 in length ; otherwise a.s in /. concolor, 

 the color more yellowish. L. 12 inches. Mississippi Valley, scarce.* 

 (caatfineus, chestnut color.) 



Trhlhynmyzon caxlmietis, GiRARD, Pac. R. K. Surv., 381, 1858, Galena, Minnesota. 



Lhlliyiimyzon hirndo, GiRARD, I. c, 3S2, Fort Smith, Arkansas. (Tyjic, Nci. 980.) 



Pelmiiiyznn canlanenK, Jordan AGilbert, Synopsis, 808, 188:i, and Jordan & Fordice, I.e., 281, 1836; 



Gi'NTHER, Cat., VIII, 507, 1870. 

 Ichthyomyzon hirndo, GiiNTHER, Cat., Vlll, 507, 1870. 



8. ENTOSPHENUS. Gill. 



Entoophcniia, GiLL, Proc. Ac. Nat. Sci. Phila., 18G2, 331, {Iridfiilaliis, name only); Jordan A Gil- 

 bert, Synopsis, 7, 1883 (IridenUdiis). 



Lampreys of large size, with the supraoral lamina forming a crescent- 

 shaped plate on which are 3 cusps, the middle one little smaller than 

 the others; anterior lingual tooth wedge-shaped, its edge almost straight 

 and finely pectinate; lips fringed; buccal disk moderate, its teeth com- 

 paratively few ; dorsal fins separate. One species, a large anadromous 



* Recorded from Galena, Minn. (Giranl); Mill Creek, Shawnee Co., Kans. (Cragiu); Fort 

 Smith, Ark. (Girard); Forlorn Hope, La. (Bean); Manitoba (Evennann). 



