PROCEEDINGS OF UNITED STATES NATIONAL MUSEU>r. 021 



orbital space strongly comcx transversely. Cheeks Avith three rows of 

 scales. 



(J ill-rakers rather smjill,but longer and stronger than mB./urcatnm, 

 the longest about one-third the diameter of the orbit. 



Scales moderate, averaging rather smaller than in J), furcation, abouL 

 5-70-1;;. 



Spinous dorsal comparatively low, the tirst spine short, tiie otlK-rs 

 rapidly increasing to the fifth, after which the others are nearly of ecpial 

 length, but gradually increasing to the last. The first soft ray is a little 

 higher than the highest spine. The other soft rays are gradually short- 

 ened. 



The caudal fin is deeply forked, the lobes being about eiiual. In 7). 

 furcatum the uj^per lobe is evidentty the longer. Anal hn low, its s])ines 

 moderately developed. Pectorals not reaching to the tips of the 'ven- 

 trals, which scarcely fall short of the liist anal si)inc. 



Fin rays : D. X, 23 ; A. Ill, LM). 



Coloration light dusky oli\e above, silvery below, with jjearly reflec- 

 tions. Scales above the axis of the body each with a golden-red spot 

 at base, the outer margin of the scales tinged with light blue. Tiu^se 

 spots fade in alcohol, but are conspicuous in life, forming reddish 

 streaks along the rows of scales. 



Membrane of dorsal, anal, aiul ventral tins liglit olive-green. Traces 

 of a dark shade on upper part of first rays of soft dorsal. No black at 

 base of dorsal. A distinct black blotch on upper third of first eight- 

 rays of the anal. Ventrals broadly tipped with reddish hlacJc, as in Ihjper- 

 proropoii argenteua. Pectorals and caudal entirely plain, the black edg- 

 ing to the latter fin, characteristic of D. furcatum, being entirely want- 

 ing. Premaxillaries and end of snout distinctly dusky. Iris silvery, 

 reddish above. 



In Ditrema furcatum the color is nearly plain, i)ale, olivaceous, and 

 silvery, the scales with bright reliections, but without distinct red nmrk- 

 in^s. The sides are more silvery than in J>. atripcs, and there are more 

 black punctulations. The naked ])ortion of the base of the soft dorsal 

 is black. There is no dark shade on the ventrals, and the caudal is dis- 

 tinctly margined with black behiiul. The dark anal sjjot is similar in 

 the two species, but it is souietimes wanting in 1). furcatum. 



The species Ditrema argyrosoma (Phanerodon argyrosomus Gill, 3m- 

 blotoca argyrosoma Girard), if distinct from Ditrenia fnrcatiim, is un- 

 known to us. It differs, according to Girard, in having the anal III, 21, 

 but the types had been mutilated ami this count may, i)erhaps, be erro- 

 neous. 



Proc. Nat. Mus. 80 21 Oct..'3T, |S80. 



