796 Bulletin 47, United States National Museum. 



356. MENIDIA (Bonaparte) Jordan & Gilbert. 



(SlLVERSIDES.) 



Menidia, BONAPARTE, Fauna Italica, about 1836, (no type indicated, menidia doubtless intended). 

 Argyrea, DE KAY, New York Fauna: Fisbes, 141, 1842, (notata; name preoccupied). 

 Menidia, JORDAN & GILBERT, Synopsis Fish. N. A., 407, 1883, (menidia). 



Body elongate, more or less compressed. Head oblong, compressed ; belly 

 before ventrals more or less rounded in section, not compressed to an edge. 

 Mouth small, the gape curved, very oblique, usually not reaching the 

 eye ; lower jaw short and weak ; maxillary slipping entirely under pre- 

 orbital ; jaws each with a band of simple, usually villiform teeth. Pre- 

 maxillaries very freely protractile, their spines comparatively long, nearly 

 equal to the eye, extending backward beneath a fold of skin which con- 

 nects the bases of the maxillaries ; posterior part of premaxillaries 

 broad. No teeth on vomer or palatines. Both dorsals short, the usual 

 radial formula being D. V-I, 8; first dorsal usually but not always in 

 front of anal ; soft dorsal and anal scaleless. Scales rather large, entire. 

 Species numerous, probably all American, all of moderate or small size, 

 some of them entering or inhabiting fresh waters. (Menidia, an old name 

 of some small silvery fish, from fj-rjvr), the moon.) 



a. Scales moderate or large, 36 to 50, those of back entire or slightly crenate; soft dorsal and 



anal mostly scaleless; teeth moderate. 

 b. Anal rays I, 15 to 18, rarely I, 19; belly very broad, not at all compressed. 



c. Scales 38 or 39. Origin of spinous dorsal just before vent and midway between tip 



of snout and base of caudal. 



d. Snout longer than eye, about 2% in head; body deep, the depth 5 in length; 



soft dorsal I, 8 or 9. PENINSULA, 1161. 



dd. Snout shorter than eye, about 3% in head; body slender, the depth 5% to 7 



in length; soft dorsal usually I, 10. GRACILIS, 1162. 



cc. Scales 47. Origin of spinous dorsal nearer base of caudal than tip of snout. 



AUDENS, 1163. 

 bb. Anal rays I, 22 to 24. 



e. Scales 45 to 48. Body slender, depth 5% to 6 in length. 



/. Dorsal spines 6; scales 48; head 4%. GILBERTI, 1164. 



ff. Dorsal spines 4; scales 45 or 46. 



g. Head 4% in length; dorsal inserted nearer tip of caudal than end of snout. 



SARDINA, 1165. 



gg. Head 5 in length; dorsal midway between tip of snout and base of caudal. 



NOTATA, 1166. 



ee. Scales 36 to 40; spinous dorsal inserted over front of anal; pectorals rather long. 

 h. Body rather stout, teeth stronger than usual. Front of dorsal nearer base of 

 caudal than tip of snout; belly slightly compressed. MENIDIA, 1167. 



hh. Spinous dorsal inserted behind front of anal. 



i. Scales 36. Depth 5 in length; head 4%. GUATEMALENSIS,* 1168. 



ii. Scales 41. Pectoral much longer than head; snout short. 



PACHYLKPIS,* 1169. 



CM. Scales small, entire, about 56 in longitudinal series; dorsal rays V-I, 9; anal I, 24; body 

 slender, its depth 6%; teeth very weak. CLARA, 1170. 



* The character of the scales has not been verified in pachylepis and guatemalensis. Both species 

 doubtless belong to Thyrina. 



