42 TKLKOSTO : EVENTOGNATIll. — XII. 



c. Pectoral spines moderate, the inner scrrs) weak, not half diameter of 

 Rpine, the outer stronf^er, retrorse, body elongate; coloration nearly 

 uniform, the tins darker cdjjed. 

 d. Pectoral opine short and weak, about 3 in head in adult. 



61. N. exilis Nelson. Head small, rather narrow, (leprossod, 4 

 in length ; (li'|)tli C ; pectoral spine retrorse-serrate without, with 6 

 small teeth within ; humeral ])rocess obscure; jaws suheipial. A. 

 14 to 17. L. i. Wis. to Kansas. (A', elassochir Swain & Kalb.) 

 (Lat., slim.) 



dd. rectoral spine longer, about 2 (1| to 2i) in head. 



62. N. insignia (Richardson). Head rather broad, flat and 

 thin, the uj>per jaw project injj ; head 4}; depth fi. A. 14 to 16. 

 L. 10. Pa. to iS. C, common E. (Lat., remarkable). 



cc. Pectoral spine very strong, curved, more than half head, ita posterior 

 serrn* recurved, their length about equal to diameter of spine, the 

 anterior serne small. 

 e. Color much variegated; adipose fin deeply notched, but not separated 

 from C 



63. N. miuruB .Jordan. Grayish ; top of head, tip of dorsal, 

 middle of adipo.>ie fin, and caudal black, the body with four black 

 cross-blotches; head not specially depressed eye 4^ in head; hu- 

 meral process moderate; pectoral spine Ij to 1| in liead ; head .'tj. 

 A. 13 to 15. 1.,. 5. E. N. C to ^linn. and La., abundant, (/xfi- 

 ovpoi, curtailed.) 



ee. Color nearly plain brownish, everywhere above covered with fine 

 small (lot.s; adipose tin almost or quite free from caudal. 



64. N. eleutherua Jordan. Head broad, flat, depressed, the 

 form very much as in l.cptojix olimris : humeral process obscure ; 

 eye .0^ in head; pectoral spine 1 J to 2 in heail ; head 3J; A. l."{. 

 L. 4. W-hite K., Ind., and French IJroad U.; 3 s])ceimcD8 known. 

 {(\fv0€pni, free.) 



bb. Pectoral spine entire, grooved behind; adipose fin continuous with 

 the caudal. 



65. N. gyrinus (Mitchill). Head short, broad and deep; pecto- 

 ral spine 2 in head ; jaws subetpial, yellowish brown, not blotched, 

 but with a narrow black lateral streak, sometimes witii two above 

 it. A. 15 or 16. L. 5. Hudson K. to .Minn, and La., conmion N. 

 {yvp'tvoi, ta<lj»ole.) 



Order XIL KVENTOGXATHI. (Tiii; Tlectospondy- 



LOUS FiSIIKS.) 



This proup, defineil on paje 26, contains the rrrotit majority of 

 the fresh-water fislu's of llie world. Its essential character is in 

 the modification of the anterior vertebne. as in the ycmalof/nalhif 



