SOUTH AMERICAN NEMATOGNATHI. 415 



aa. Ventral surface entirely granular. 



c. Eye 6-6* in the head to end of occipital plate; head arched above; 

 opercle.aud interopercle with spiny margins; lateral plates keeled, sur- 

 faces of all the plates entirely covered with prominent spiniferous 

 ridges; a series of large f)lates along the lateral surface of the belly. 

 Lat. 1. 22-25. agassizii 371. 



cc. Eye small, 10 or more in the head; head flattish above; lateral plates 

 not keeled. aspera 372. 



369. Rhinelepis parahybae. 



Rhinelepis parahyhce Steindachner, Susswasserfische stidostl. Bras, 

 iv, 2, pi. 2 (Parahyba); Eigenm. & Eigeum. Proc. Cal. Acad. 2d 

 Ser. ii, 42, 1889 (Kio Parahyba, at Barra do Pirahy). 



Habitat: Kio Parahyba. 



Elongate, depressed, the depth 1| in the width. 



Head broad, depressed; its width equals its length to 

 the upper angle of the gill-openings; occipital slightly 

 raised in the middle, terminating in a triangular pro- 

 cess which is bordered by 3 nuchal plates; interorbital 

 concave. Snout broad, depressed, its tip naked. 



Orbit 4 in the snout, 7i-7 in the head, 3-2f in the 

 interorbital. 



A few granules between the pectoral spines, an elon- 

 gate patch along sides of belly, a few granules between 

 the posterior margins of the ventrals, others in front of 

 the vent; the ventral surface otherwise naked. 



Lateral plates not keeled, thickly covered with minute 

 spines. 



Base of the dorsal fin equal to its distance from the 

 first unpaired plate in front of the caudal fin. 



Caudal truncate, the outermost rays prolonged. 



Pectoral spine reaching base of ventral, the ventral to 

 vent. 



Uniform dark bronze brown, lighter below. 



HeadSi; D. I, 7; A. 6; V.I, 5; P. I, 6; Lat. 1.25-26. 



Four specimens .29-. 30 m. Rio Parahyba at Barra do 

 Pirahy. Hartt & Copeland. Thayer Expedition. 



