Cope.] 1\j4. [Jan. 5, 



lamelliform lobe of the first branchial arch is simple in the G. gi/mnogenys, 

 in G. camurus and G. brachyurus its border is divided into digitate pro- 

 cesses. In my specimen of G. brasiliennis the digitate processes are pres- 

 ent but rudimental. Hensel has distinguished a species as characterized 

 among other points by the absence of scales on the cheek. Steindachner 

 does not appear to liave met with this condition in the G. brasiliensis, yet 

 he refers Hensel's species to the latter, believing that the absence of 

 scales from the cheek is an abnormality, " probably most frequent during 

 the spawning season." I find the character on the contrary to be con- 

 stant in the eight specimens of G. qymnogenys and G. camurus, which 

 are of different sizes and ages, and which are characterized by well- 

 marked peculiarities of the form of the head and the body. The scales 

 are constantly present in five specimens of the G. brachyurus, which are 

 of the same size as those of the G. gymnogenys and G. camurus, and 

 are associated with equally well-marked specific characters. I believe 

 with Von Jhring that Hensel is right in regarding the character as of 

 specific value. 



In the Geophagus gymnogenys the anterior border of the orbit is as far 

 from end of muzzle as the posterior border of the orbit is from the con- 

 vexity of the opercular border. Profile nearly straight, dorsal fin not 

 scaly at base. Cheek naked except a patch of five scales between the 



orbit and preopercle. Preorbital bone a little wider than tegumentary 



3 

 orbit. Scales 28 . Fin radii, D. XIII. 11 ; A. III. 8. Body deep ; the 



IT 

 depth contained in the length to base of caudal fi.n 2.33 times ; length of 



head in the same, three times. Pectoral fin reaching first soft ray of anal ; 

 caudal fin openly emarginate. 



Color brown, each scale with a paler centre. A dark-brown spot 

 extends over the dorsum immediately in front of the dorsal fin and 

 extends to the lateral line on each side. Two dark spots below the spi- 

 nous dorsal fin, and two below the soft dorsal, above the lateral line. A 

 dark spot below the lateral line behind the superior opercular angle, and 

 another on the side below the rays xi and xii of the spinous dorsal. Dor- 

 sal and caudal fins dusky with rather numerous oval and round pale 

 spots. A dark spot on superior part of operculum and one below eye. 



Total length, 107 mm. ; length to base of caudal fin, 87 mm. ; length to 

 base of anal, 53 mm.; length to base of ventral, 39 mm.; length of head 

 side, 26 mm. 



One specimen. 



Geophagus camurus ."sp. nov. 



Anterior border of orbit more distant from end of muzzle than the pos- 

 terior border is from convex border of operculum. Profile strongly con- 

 vex at and in front of the orbit. Form most elevated at the base of the 

 dorsal fin, then tapering posteriorly. Cheeks naked or with one or two 

 obscure scales. Preorbital bone a little wider than tegumentary orbit. 



1 



