20 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 119 



Head conic and snout obtuse in both vertical and horizontal pro- 

 files, top of head gently convex between eyes. Head 3.8 (3.8-3.8) ; 

 eye in head 3.1 (3.0-3.2); snout in eye 1.3 (1.2-1.3); least width of 

 long interorbital in gi-eatest eye diameter 1.3 (1.3-1.3). 



Premaxillary with 7 teeth; anterior and lateral teeth septemcuspid, 

 third from anterior or median cusp largest. Maxillary with 1 quadri- 

 cuspid tooth. Dentary with 6 teeth, each usually with 7 cusps. Third 

 cusp from medial or anterior end of tooth largest; sometimes central 

 cusp largest. Inner row of teeth damaged in all specimens but appears 

 to be over 10 simple conic teeth. Gill rakers 8 + 14 (one alizarin, 

 specimen) . 



Dorsal fin ii,8; anal fin iii,9. Adipose fin absent. Caudal fin -with 

 prmcipal rays 10/9. 



Anal fin of male in good condition, somewhat modified. First 

 ray small and completely hidden by a basal scale. Second ray enlarged 

 and its anterior edge expanded and carinate. Entire fin larger than 

 that of females and individual rays thickened laterally and somewhat 

 enlarged in an anterior and posterior plane. In folded position, rays 

 take an alternate position to each other with regard to median plane. 

 However, anal fin not nearly as modified as that of Nannostomus 

 digrammus. 



Radial grooves of scales belonging to that part of third horizontal 

 scale row below dorsal fin having posterior field with 1 to 3, usually 

 2 radial grooves; dorsal and ventral fields with 1 and anterior field 

 with 3 to usually 4 radial grooves. Scales in lateral series 25 in 

 single countable specimen. This specimen also with 3 perforated 

 lateral-line scales in single row behind cleithrum. Scales in a median 

 series before dorsal fin 10 in 2 female specimens. Total number of 

 vertebrae 36 (19 precaudal and 17 caudal). 



Color in alcohol. — Top of head and back light brown. Dorsum 

 at base of dorsal fin dark brown. Primary horizontal stripe dark 

 brown, extending from snout tip and lower jaw onto anterior surface 

 of eye, across lower border of fifth orbital bone and upper border of 

 fourth orbital bone to over upper limb of preopercle, finally terminat- 

 ing at posterior border of bony opercle. On body, primary horizontal 

 stripe beginning anteriorly underneath fleshy opercular flap and 

 extending through middle of fourth scale row, covering lower and 

 upper exposed portions of third and fifth scale rows respectively. 

 Primary stripe widening posteriorly until over anal fin covering 

 entire foiu-th scale row and upper half of fifth scale row. Primary 

 horizontal stripe covering entire lower half of caudal peduncle and 

 entering lower lobe of caudal fin. Its pattern over lower lobe of 

 caudal fin could not be determined due to damage. Below primary 

 horizontal stripe, sides and belly pale brown (probably silvery in 



