408 • CALIFORNIA ACADEMY OF SCIENCES. 



Base of the dorsal fin longer than its distance from 

 the adipose fin. 



Caudal very obliquely emarginate, the shortest rays 

 scarcely more than half as long as the head. 



Head with vermiculating light and dark lines, sides of 

 the body with large spots forming about 5 series on the 

 tail; all the fins with large spots; ventral surface with 

 the spots coalescing. 



Lat. 1. 27-28. Head 24-3. 



Four specimens .15-. 25 m. Rio Puty; Rio Preto; San 

 Gongallo. 



Several specimens from Goyaz resemble this species 

 but they are so much damaged as to make it impossible 

 to certainly identify them; these examples have the tip 

 of the snout naked. 



351. Plecostomus villarsi. 



Plecostomus villarsl Llitkeu, Overs. Dau. Selsk. 211, 1874, (Caracas); 



Steindachner, Fisch-fanua des Magd. Stromes, 26, pi. vii, 



1878 (notes on the type). 

 Habitat : Caracas . 



352. Plecostomus virescens. 



Plecostomus virescens Cope, Proc. Acad. Nat. Sci. Philad. 137, 1874 

 (Upper Amazon); Cope, Proc. Am. Philos. Soc. xvii, 681, 1878 

 (Periivian Amazon). 



Habitat: Maranon. 



We have been unable to assign this species to a place 

 in the key. 



Head wide, depressed; body and tail rather elongate; 

 an obtuse occipital and nuchal elevation; post and pre- 

 orbital angles well marked. A few preopercular spines. 

 Head below naked behind the mouth; teeth numerous, 

 acutely incurved. Posterior lip entire, smooth. Eye 4 

 in head, 2 in interobital. Base of dorsal equals its dis- 

 tance from the adipose plus one scutum. Pectoral spine 

 reaching a little beyond base of ventral. 



Head4i. D. I, 7. A. 5. (Cope.) 



