eigenmann: the FRESHWATER FISHES OF BRITISH GUIANA 465 



Mugil brasiliensis (not of Agassiz) Gunther, Catalogue, III, 1861, 431. — Jordan 



and Gilbert, Synopsis Fishes North America, 1883, 403. 



Several specimens, the largest 238 mm. Georgetown market. (C. M. Cat. 

 No. 1472a-c; I. U. Cat. No. 12399.) 



Order PERCOMORPHI. 



Key to the Families of Percomorphi. 

 a. Lateral line continued on the tail. 



6. Anal spines 2; caudal pointed Sciaenidae, XXI. 



bb. Anal spines 3; caudal forked Centropomidae, XXII. 



aa. Lateral line if present not continued on the tail. 



c. Dorsal spines strong, the spinous dorsal continuous with the soft dorsal. 



d. Nostrils single; lower pharyngeals united. Lateral line interrupted near the end of the spinous 



dorsal Cichlidae, XXIII. 



dd. Nostrils double; lower pharyngeals separate. No lateral line Polycentridas, XXIV. 



cc. Dorsal spines weak, the spinous dorsal not continuous with the soft dorsal Gobiidae, XXV. 



Family XXI. SCI^NID^. 



Key to the Genera of Sci/enim:. 80 

 a. Teeth not villiform; lower jaw prominent; edge of the preopercle entire; second anal spine weak, adnate to 

 the first ray, the first spine minute or obsolete. (Otolilhinw.) 



b. Canines not lance-shaped, tapering from the base; anal rays 7 to 13 Cynoscion. 



bb. Canines lance-shaped, widened near the tip, then abruptly pointed, those in the premaxillary largest; 



about two canines on front of the lower jaw on each side; teeth in outer series of upper jaw some- 

 what enlarged and lance-shaped Macrodon. 



aa. Second anal spine usually well-developed and joined to the first ray by a distinct membrane. (Sciamina.) 



c. Lower jaw without barbels. 



d. Preopercle without teeth or serrations, its membranaceous margin entire, crenulate or ciliate. 



e. Skull excessively cavernous, soft and spongy to the touch; interorbital space very broad; 



mouth large and oblique; teeth subequal, all villiform, in narrow bands; lower jaw 



projecting. Pseudobrancliia: developed Nebris. 



ee. Skull firm, not excessively cavernous; interorbital space not very broad; preorbital not turgid. 



Teeth not villiform, but more or less unequal, those of the upper jaw biserial, the inner 



series somewhat enlarged. Scales of the lateral line considerably enlarged, almost 



entirely concealed by smaller ones. Pseudobrancliia; small, often obsolete on one side. 



Plagioscion. 



dd. Preopercle armed with sharp teeth or seira\ Head very broad; interorbital space flattish and 



very cavernous. Soft dorsal and anal fins densely scaled. Second anal spine stout. 



Stelliferus. 

 cc. Lower jaw with barbels. Lower jaw included, its teeth villiform, in bands. 



/. " Pseudobranchiae well-developed, pectoral fin not elongate." 



g. Barbels three, slender, and at the symphysis of the lower jaw; mouth small and inferior; pre- 

 orbital turgid and cavernous, somewhat translucent; caudal fin rhombic. Preopercle 

 finely serrate Pachypops. 



60 This account of the Sciaenidae was prepared by Mrs. Marion Durbin Ellis. 



