1906.1 



NATURAL SCIENCES OF PHILADELPHIA. 



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a little anterior. Mouth superior and mandible well protruding in 

 front, cleft nearly vertical. Maxillary small and vertical. Teeth 

 large, sharp, crenulate, uniserial, and two median mandibulars largest 

 and most conspicuous. Tongue rather broad, rounded, and hardly 

 free. Anterior nostril in a fleshy tube about equal to diameter of pupil 

 in length, lateral, and nearly midway in length of snout. Posterior 

 nostril large, a little inclined, slit-like, and close to middle of anterior 

 rim of orbit. Interorbital space broad and nearly flattened. 



Gill-opening extending about opposite posterior margin of pupil. 



Fig. 16. — Pithecocharax ucayalensis Fowler. 



Rakers short weak fleshy protuberances, and moderately numerous. 

 Filaments well developed. 



Scales mostly fallen, large, evidently in rows parallel with lateral 

 line, and also apparently all of more or less even size. Base of caudal 

 apparently scaly. Lateral line evidently complete, and of simple 

 tubes. 



Origin of dorsal nearly midway between tip of mandible and base of 

 caudal. Origin of adipose fin placed about last fourth in space between 

 origin of dorsal and base of caudal. Anal inserted well behind dorsal, 

 or near middle of space between end of ventral and base of caudal. 

 Pectoral low, and though' damaged apparently not reaching ventral. 

 Ventral inserted a short distance before origin of dorsal, and though 

 also damaged not reaching perhaps more than half way to anal. 



Color in alcohol brown, lower surface and fins paler. Body with 



