31. CYPRINIDiE HYBOGNATnUS. 155 



ISO. Z. sidci'iuni (Cojie) .Tor. 



l^hysiognomy of Ajwcope. Body fusiform. Head rather small, acu- 

 minate. JNEoutli terminal, the upper jaw the longer, maxillary reaching 

 line of orbit. IMouth forming more than a semicircle. Lower jaw hard, 

 jess attenuate than is usual in HyhognatJms. Eye small, 4j'y in head. 

 Fins long, the ventrals reaching anal. Color dark iron-gray above, a 

 darker band of the same along the sides, above the lateral line, extend- 

 ing from the end of the snout to the middle of the caudal. Ilead 4 ; 

 depth 4. D. 8 ; A. 7 ; Lat. 1. 88 ; teeth 4-4. Arizona. {Co2)c.) 



(Jlijhorhynchus sidcrius {lapsus for Ilijhtxjnathns) Cope, Zoiil. Wheeler's Expl. W. lOOtli 

 Mer, V, G70, ld7(5.) 



** Scales moderate, 55-00 in the course of the lateral line. 



1§1. Z. pluiMboiiSBi (Grd.) Jor. & Gilb. 



Body rather slender. Head moderate, rounded in front. Color uni- 

 form, sometimes a black spot at the base of the caudal. D. 8 ; A. 7 ; Lat. 

 1. 58 ; teeth 4-4. Arkansas and Indian Territory. (Gimrd.) This spe- 

 cies may, perhaps, be referable to Hybognathus. 



(Dionda phimhea and spadlcea Girard, Proc. Acad. Nat. Sci. Pliila. 1856, 178 : Hyho- 

 rhynchus punictus, Grd. 1. c. 179 : Dionda fjrisca, Grd. U. S. Pac. E. R. Surv. x, 230.) 



77.— MYB©G]^ATiaUS Agassiz. 



{Alf/oma and Dionda Girard.) 



(Agassiz, Amer. Journ. Sci. Arts, 1855, 223: tyi)e Hyhognathns nuclialis Ag. ) 



Body elongate, somewhat compressed. Mouth horizontal. The jaws 

 normal, sharp-edged ; lower jaw with a slight, hard protuberance in 

 front ; no barbel ; upi)er jaw protractile. Teeth 4-4, cultriform, with 

 oblique grinding surface and scarcely any hook. Alimentary canal 

 elongate, about 4 times the length of the l)ody. Peritoneum black. 

 Scales large. Lateral line continuous. Dorsal over ventrals. Anal 

 basis short. Size moderate. Species numerous ; mostly southwestern, 

 and little known. {''>i^<k, gibbous ; y^dOo^, j-i^v.) 



* Body comparatively elongate, little compressed, llic depth less than two-sevcuths of 

 the length. 

 c. Suborbital bones comjiaratively long and narrow. 



slightly included ; the premaxillary below the level of the eye; the maxillary just 

 reaching the front of the eye. Lower jaw thin-edged, with a slight symphyseal knob. 

 Eye small, G in head. Scales small. Lateral line complete, decurvcd. Dorsal 

 slightly behind ventrals. Dusky bluish above ; everywhere with dark points. A 

 black spot at base of caudal. Head 4; depth 4-18. D. 8 ; A. 7 ; scales 10-5(5-8 ; teeth 

 4-4. L. 7 inches. Lake Tnpataro, Guanajuato, Mexico (west of the Sierra Madre). 

 (Jordau, Proc. U. S. N.at. A1n« t^^^ -v-o x 



