FISHES — PERCIDAE — POMOTIS FALLAX. 



27 



List of specimens. 



6. POMOTIS FALLAX, B. & G. 

 Plate VIII, Figs. 9—12 ; Plate IX, Figs. 5—12, & Plate X, Figs. 1—7. 



Spec. Char. — Body sub-circular or sub-elliptical. Head moderate ; snout bluntly sub-conical. Mouth large ; posterio^ 

 extremity of maxillary extending to the anterior rim of the pupil. Eye moderate. Edge of preopercle not crenated. 

 Opercular flap very large. Spinous portion of dorsal fin of medium height ; its origin situated opposite the base of the 

 pectorals. Caudal emarginated posteriorly. Tips of ventrals extending to the anterior margin of the anal. Blackifh or 

 reddish brown ; lighter beneath than above. Sides of head provided with bluish spots, sometimes confluent into irregular 

 hues. A black patch upon the base of the dorsal fin. 



SYH.—Pomotis fallax, B. & G. Proc. Acad. Nat. Sci., Philad., VIII, 1854, 24. 



Pomotis convexifrom, B. & G. Proc. Acad. Nat. Sci., Philad., Vll, 1854, 24. 



This is the most polymorphic species which we have so far met with amongst fresh water 

 fishes. We have caused it to he fully illustrated in order to give a correct idea of its most 

 prominent variations. The species which we had formerly enumerated under the name of P. con- 

 vexi/rons is one of these. 



A comparison of the figures on Plate X will show that the upper outline of the head and 

 Tjody both are subject to very great variations, and that the dorsal fin itself participates in giving 

 to the region it belongs its diversified aspect. Again the snout is more or less protruding, 

 affecting considerably the physiognomy of the species, as well as the opercular flap, which, in 

 some specimens, reaches most abnormal proportions. (Fig. 5.) 



This species was first collected by the United States and Mexican boundary commission, 

 to whose Report we would refer our readers. 



References to the figures. — Plate VIII, fig. 9, exhibits, size of life, an immature specimen of 

 Pomotis fallax, from Eio Seco, Texas. Fig. 10 is a dorsal scale. Fig. 11, a scale from the 

 lateral line. Fig. 12, a scale from the abdominal region. 



Plate IX, fig. 5, represents, size of life, Pomotis fallax, from Sans Bois creek, a tributary of 

 Canadian river. Fig. 6 is a dorsal scale. Fig. 7, a scale from the lateral line. Fig. 8, a scale 

 from the abdominal region. 



Fig. 9, of the same Plate, exhibits an immature specimen, size of life, from Rio Medina, 

 Texas. Fig. 10, a dorsal scale. Fig. 11, a scale from the lateral line. Fig. 12, a scale 

 from the abdominal region. 



Plate X, figs. 1, 5, 6 and 7 represent various outlines of the same species, all from a tribu- 

 tary of Gypsum creek, itself an aflluent of the Canadian river. Fig. 2 is a dorsal scale. Fig. 

 3, a scale from the lateral line. Fig. 4, a scale from the abdominal region. 



