Freshwater Fishes from Costa Rica. 461 



III. Origin of anal below fourth or fifth dorsal ray ; origin of dorsal 

 equidistant from end of snout and base of caudal ; 28 to 30 scales 

 in a longitudinal series 10. petenensis, Giinth., 



[1866. 



IV. Origin of anal below the middle of dorsal ; origin of dorsal equi- 

 distant from end of snout and anterior part of caudal ; 23 to 27 

 scales in a longitudinal series. 



Depth of body about 2f in the length, length of _ [1859. 



head about 4 (in specimens of 50 mm.) .. 11. couchiana, Girard, 

 Depth of body 2 to 2| in the length, length of [1866. 



head 3^ to 3§ (in specimens of 60 mm.) . . 12. maculata, Giinth., 



Mugilidae. 

 11. Agonostomus percoides, Giinth. 



Rio Iroquois. 



Two specimens : one of 135 mm. in every way similar to 

 the type of the species ; the other, 270 mm. in total length, 

 with thick upper lip. 



Xenorhynchichthys, gen. no v. 



Differs from Joturus, Poey, in the absence of teeth on the 

 palatines and pterygoids. 



12. Xenorhynchichthys stipes, Jord. & Gilb. 



This species has been placed by Jordan and Evermann in 

 the synonymy of Joturus pichardi, Poey, but it is quite 

 distinct. In the type of Agonostomus globiceps. Giinth., 

 which seems to be identical with J. pichardi, the vomerine 

 teeth form a triangular patch, bands of teeth are present on 

 palatines and pterygoids, the snout is vertically truncated, 

 and the maxillary extends a little beyond the vertical from 

 the anterior edge of the eye. 



In four young specimens of X. stipes, 150 to 190 mm. in 

 total length, from the Rio Iroquois, the vomerine teeth form 

 a transverse ovate patch, there are no palatine and pterygoid 

 teeth, the snout is obliquely truncated, and the maxillary 

 extends to below the middle of the eye. In these examples 

 the soft dorsal, anal, and caudal fins have large blackish 

 spots or oblique bars. As in J. pichardi the anal fin is 

 formed of II 11 rays, the first spine very small, the two first 

 articulated rays un branched. 



Cichlidae. 



13. Cichlosoma septemfasciatum, sp. n. 



Depth of body If to 2^ in the length, length of head 3 to 

 3|. Snout as long as or shorter than postorbital part of 



