290 PROCEEDINGS OF THE ACADEMY OF [1883. 



anal spine Q^. Anal spines 3 in nnmber. Caudal fin long. 

 This s[)ecies is allied to G. planiieri. but the back is less elevated 

 and the spines smaller than in the latter. Gerres rhombeus 

 C. & V. is a very diflTerent species, closely allied to Gerres 

 peruvianua, but with two anal spines onl3\ It occurs on both 

 sides of the Isthmus of Panama. 



24. Gerres brevimanus Giinther. 



(Giinther, Proc. Zool. Soc. Lond., 1b64, 152.) 



This species is distinct from G. Hneatus (Humboldt), although 

 closely allied to it. Only the original t^^pe is yet known. On 

 this I have the following notes : — 



Head 3;^ in length ; depth 2^ ; eye 3^ in head. Coloration of 

 Gerres Hneatus. Back much lower than in the latter, and pectoral 

 fins very much shorter; their length li in head ; their tips not 

 reaching nearly to tips of ventrals, which are 1;^ in head ; caudal 

 3 in body. Preorbital very little serrate, almost entire. Preo- 

 percle weakly serrate. Second dorsal spine If in head; second 

 anal spine 1|. Teeth small and short. No black on base of 

 pectoral, or on lower fins. Spinous dorsal dusky above. Frontal 

 groove broad and naked, as in G. Hneatus. 



25. Opistliojnathus punctata Peters. 



(Peters, Berl. Monatsber., 1869.) 



Type, 70G4, Berl. Mus. ; about one foot long, from Mazatlan. 



Head everywhere finely speckled with black, the body more 

 coarsely and irregularly spotted. Pectoral finely and closely 

 speckled, its edge plain. Ventral fin dusky, similarly marked. 

 Dorsal without large black blotch, finely spotted, the spots 

 Lehind gradually forming the boundaries of white ocelli, the base 

 of the fins having rings of white around black spots, the upper 

 l^art with dark rings around pale spots. Caudal with pale spots, 

 its edge, like that of the dorsal, somewhat dusky, not black. 

 Anal with a bro^d, blackish edge, and with dark spots, those near 

 the base of the fin largest. Lining membrane of maxillary with 

 the usual bands of white and inky black. 



Scales very small, about 125 in lateral line. Dorsal spines 

 continuous with the soft ra3's. D. 28; A. 18. No vomerine 

 teeth. Maxillar^'^ very long, extending slightly beyond head. 



Only the type of this species is yet known. 



