284 PROCEEDINGS OF UNITED ST<VTES NATIONAL MUSEUM. 



The species of tliis geuns are all American. Those known to us may 

 be compared as follows: 



a. Mouth compaiatively large, the maxillary extending to below the eye; gill-raker.s 

 tiibercnlate or minute. 

 1). Outer teeth of upper jaw much enlarged, more than half length of posterior 

 uostril; snout protruding well l)eyond premaxillaries; scales ou breast 

 large, regularly arranged. 

 c. Soft dorsal rather short (rays less thau I, 2:i); coloration plaiu. 



d. Spinous dorsal elevated, its longest spines reaching past front of soft dorsal; 

 snout very i)romiuent, its tip slightly turned upward, xii'ojecting beyond 

 premaxillaries for a distance about equal to the large eye; maxillary 

 shortest, 3^ in head ; posterior nostril oblong; upper caudal lobe elongate; 

 tip of spinous dorsal black ; lower tins pale or somewhat dusky. D. X-1, 22. 



Pacific coast of tropical America Nasus.* 



dd. Spinous dorsal not elevated, the longest spines not reaching soft dorsal; 

 snout bluntisli, projecting beyond premaxillaries for about half diameter 

 of eye; maxillary long, 3 in head; posterior nostril nearly round; upper 

 caudal lobe not produced; pectoral large; lower fins mostly black. D. 



X-I, IS. Pacific coast of tropical America Panamensis.! 



cc. Soft dorsal rather long (D. X-I, 24); spinous dorsal moderately elevated, its 

 tip reaching front of second dorsal ; snout short, rather sharp, projecting 

 beyond premaxillaries for a distance equal to about half eye; maxillary 

 moderate, 3 in head; posterior nostril broad-ovate; lower caudal lobe 

 longest; pectoral rather large; coloration nearly x>lain, or with faint ob- 

 lique dusky bars; pectoral and lining of opercle black. South Atlantic 



and Gulf coasts of United States Alburnus. 



hb. Outer teeth of upper jaw moderately enlarged, less than half length of posterio 

 nostril; snout moderately protruding; scales ou breast large; spinous dor- 

 sal high, the longest spine filamentous (in the adult) reaching past front of 

 second dorsal, usually higher than body below it; gill rakers reduced to 

 minute tubercles. Body always with distinct oblique bauds, the anterior V- 

 shaped; a dark lateral baud, distinct posteriorly, and extending ou lower 

 lobe of caudal; lower fins blackish; lining of opercle mostly pale. D. 

 X-I. 2G. Cape Cod to Gulf of Mexico NEBt'LOSus. 



aa. Mouth comparatively small, the maxillary less than one-third head, barely reach- 

 ing eye; outer teeth of upper jaw scarcely enlarged; snout little })roject- 

 ing; scales ou breast small, irregular; coloration plaiu, the back and 

 sides ijometimes with faim undulating streaks. D. about X-I, 24. 

 e. Pectorals, veutrals, and anal black; snout bluutisb, scarcely projecting; 

 posterior nostril oblong; pectoral large, li in head: depth, 4^ iu hngfb; 



scales, 9-60-14. Southern California UxDULATtjs. 



ee. Pectorals, ventrals, and anal pale; lining of gill cavity pale. Snout some- 

 what projecting; pectorals shortish. If in head. 

 /. Upper lobe of caudal longer thau lower; scales about 9-60-13; 2.5 scales 

 in an oblique series forward from vent to lateral line; axillary scale one- 

 third length of pectoral; posterior nostril short, one-third diameter of 

 orbit; snout very little inojecting; gill-rakers very short, 4 or 5 on 

 lower part of arch ; depth, 4^ in length. Pacific coast of tropical Amer- 

 ica Eloxgatus. t 



* TJnibrina nasus Giiuther, Fish. Ceutr. Amer. 1869, 426. Mazatlan (Gilb.) ; Panama 

 (Gthr.; Gilb.). 



\Umhrina panamensis Steindachner, Ichth. Beitr. iv, 9, 1875. Mazatlan (Gilb.); Pan- 

 ama (Steiud. ; Gilb.). 



t Umbr'nia cloiifialn Gthr. Proc. Zool. Soc. Loud. 1864, 148. Mazatlan (Gilb. ) ; Chiapam 

 (Gthr.); Panama (Steind. ; Gilb.). 



