NATURAL SCIENCES OF PHILADELPHIA. 



13Y 



Two specimens from Nauta. 

 Plecostomus virescens, sp. nov. 



Head wide, depressed, muzzle moderately elongate; bod}^ and 

 tail rather elongate. There is a very obtuse occipital and nuchal 

 elevation, while the post and preorbital angles are well marked. 

 A few preopercular spines. Head below naked behind the mouth. 

 Teeth numerous, acutel}' incurved. Posterior lip entire, smooth ; 

 beard sliorter than diameter of orbit. The latter is one-fourth the 

 length of the head, and one-half the flat interorbital space. Length 

 of head 4.25 times in the total minus caudal fin. Radii D. I. 7, I; 

 C. I. 14, I; A. 5 ; V. I. 4 ; P. I. 6. Basis of dorsal equal space 

 between it and second dorsal plus one scutum, and equal the length 

 in front of it to tlie middle of the interorbital region. Pectoral 

 spine reaching a little bej'ond base of ventral. Scuta 26 4, with- 

 out keels but with numerous rugose ridges. 



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