1418 Bulletin 47, United States National Museum. 



soft rays; anal and dorsal closely scaled; anal spines scarcely distin- 

 guishable. Pectorals long, 1^ in head, reaching much beyond ventrals; 

 ventrals inserted below base of pectorals, 1? in head; caudal double trun- 

 cate, the middle rays \\ in head. Coloration pale. Length 1 foot or a 

 little more. Sandy shores about Panama, rather common. Here described 

 from numerous specimens brought by Dr. Gilbert from Panama. Vciy 

 close to Nebris microps, the scales apparently smaller. (Ceordg, soft-boiled, 

 referring to the soft, very spongy head.) (Types, No. 433, and others, 

 L. S. Jr. Univ. Mus. Coll. Gilbert. ) 



575. PLAGIOSCION, Gill. 



Plagioscion, Gill, Proc. Ac. N.it. Sci. rhila. 1861, 82 (a generic description only ; no species 



or type being indicated.) 

 Diploh'pift, Steindachner, Beitriige zur Kenntniss der Scia^noiden Brasiliens, 2, 1863, 



{Xijvamosismmt(s) ; name preoccupied in Hymenoptera. 

 Flaijio acion, Jordan & Eigenmann, Review Scisenidw, 380, 1889 {squamosigsimus) . 



This genus consists of fresh water Sciienoids, inhabiting the rivers of 

 South America, probably occasionally descending to the sea. It is closely 

 allied to CorvuJa and Pseudotolitkus, from both of which it is well dis- 

 tinguished by the peculiar squamation of the lateral line, a character 

 which suggested to Dr. Steindachner the name Diplolepis, the scales of the 

 lateral line being covered with smaller ones. Like most fresh-water 

 fishes, the species of Plagioscion are subject to many variations, especially 

 in regard to the size of the second anal spine. But 3 or 4 of the many 

 nominal species seem to be valid. We attach to this genus, with doubt, a 

 species {heterolepis) which we have not seen and which may belong to 

 OpMoscion. {nXayio';, oblique; duiov, Scia'/tia.) 



a. Second anal spine small, scarcely longer than eye, 4 to 5J times in length of head, 

 ?>. Dorsal rays X-I, 31 or 32. squamosissimus, 1797. 



bb. Dorsal rays X-I, 28 or 29. heterolepis, 1798. 



aa. Second anal spine very large'and strong, 2 to 3 in head; dorsal rays X-I, 32 or 33. 



SURINAMENSIS, 1799. 



1797. PLAGIOSIIOX SQUAMOSISSIMUS (Heckel). 



Head 3^; depth 3^. D. X-I, 31 or 32; A. II, 7; scales (large ones or 

 pores) 49 to 53. Second anal spine small, scarcely longer than eye, its 

 length 4 to 5^ in head; teeth of lower jaw with the inner series consider- 

 ably enlarged; snout of moderate length, 5 in head; eye 5i; maxillary 2i^ 

 in head; gill rakers rather long, j-(-12; pseudobranchiic usually small on 

 one side and obsolete on the other; upper part of the preopercle crenulate 

 on its bony margin ; pectoral fin short, If in head; anal spine 4.} to 5i, its 

 length subject to much variation; caudal convex; ventrals filamentous at 

 tip. Lower pharyngeals narrow, armed with villiform teeth. Color sil- 

 very, darker above, the axil with a large black spot. Rivers of Guiana 

 and Brazil, generally common southward; no Guiana specimens seen by 

 us, the specimens here described from Obidos and Coary. 



Hcicena squamosissima, Heckel, Annaleu des "Wiener Museum, ii, 438, 1840, Amazon; 



Steindachner, Beitr. zur Kenntniss der Fisch-Fauna Sud- Americas, 3, 1879. 

 ?Scioena rubella, Schombdrgk, Naturalists' Library, Fishes of Guiana, ii, 133, 1843, 



Rivers of Guiana. (D. IX, 34 ; A. II, 6 ; anal spines presumably small.) 



