246 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxn. 



KEY TO GENKRA. 



a. GERRIN.E. Dorsal iiii continuous, deeply notched; anal spines, o or 2. 



b. Second interhiiemal spine normally developed, not forming a hollow cylinder, 

 the air-bladder not entering it, but its tip forking, extending on each side of 

 it. 

 c. Second interhjemal spine long, spear-shaped, anal spines 8. 

 (I. Preopercle entire; second anal spine moderate. 



e. Dorsal spines, 9 Xytitnma, 1 



ee. Dorsal spines, 10 G'erreomorpha, 2 



1. XYST^^MA Jordan and Evermann. 



Xysta'nta Jordax and EvEKiMANN, Proc. Cal. Ac. Sci., 1895, p. 471 {cinereui<). 



This genus differs from Gern-'s in having the preopercle entire. The 

 body is compressed, but not greatly elevated, and the second anal and 

 fourth dorsal spines are less enlarged than in Gerres. Dorsal spines 

 always 9; anal spines, 3. The second interluemal is long and spear- 

 shaped, not hollow, and not receiving the air-bladder, its structure as 

 in Gerres. Usually the air-bladder is forked, passing on each side of 

 the interhannal spine. Species numerous, chiefly Asiatic, only the 

 type-species being American. 



[^varov^ spear-shaft; aijj.a^ blood, for interhtemal.) 



I. XYSTiEMA ERYTHROURUM (Bloch). 



KUROSAGI (BLACK SMELTi, AMAGI i SWEET-FISH i, SIJUGARA (CHICKADEE.) 



Spams erylJiroarus Blovh, Ichth, VIII, 1790, p. 23, pi. cclxi (Japan). 



Gerres. equula Schlegel, Fauna Japonica, Poiss., 1843, p. 76, pi. xl, tig. 1 



(Nagasaki). — Bleeker, Nieue Nalez, Japan, XXV, 1857, p. 92 (Nagasaki). 

 ? Gerres japonmis GDnther, Cat., IV, 1862, p. 260 ( Amoy; Canton. Said to have 



D. IX, 10). (Not of Bleeker.) 

 ? Gerres japonicas Rutter,''' Proc. Ac. Nat. Sci., Phila., 1897, j). 76 (Swatow, 



China). 

 Xystiema oyena S.mith and Pope, Proc. U. S. Nat. Mus., XXXI, 1906, p. 478 



( Yamagawa, near Kagoshima). (Not of Forskal) . 



Ilahitat. — Southern Japan, perhaps southward to China, common in 

 sandy bays northward to Wakanoura. 



Head 3i in length; depth %\ to ?,; D. IX, 10; A. Ill, 8; eye 3 to 3i 

 in head; scales 4i-4-J:-9. 



Bod}' elliptical-compressed, rather more elongate and less angular 

 than usual in Xyst^ma; silvery part of maxillar}' about twice as long 

 as deep; groove on top of head short, obtuse behind; dorsal rather 

 low, its longest spine If to 1| in head; second anal spine 3 to 3iT in 

 head; pectoral as long as head; ventral \\ in head; distance from ven- 

 tral base to anal greater than length of head; gillrakers very short 

 and sharp, 5 + T. 



«This specimen having the depth 2| in length, the anal spine f depth of body, 

 nuist belong to a distinct species, perhaps Xysixma oyena. 



