Dec, 28, 1916. Fishes of PANAMA— MEEK AND HILDEBRAND. 335 
‘Color bluish black above; sides mostly silvery, the margin of scales 
brown; pale below. Very young often with a dark lateral band, which 
later becomes only faintly visible. A dark caudal spot present at all 
ages, but most distinct in young. The spines of first dorsal black, the 
membranes yellowish green; second dorsal and caudal yellowish green 
at base; ventrals yellow; pectorals plain translucent. Very young some- 
times with reddish fins. 
‘There are 118 specimens, ranging from 40 to 255 mm. in length, in 
the present collection which we have identified as this species. These 
were collected at various points on both slopes of Panama, mostly in the 
lowland streams, some even were taken in brackish water, and a few 
are from upland streams. On the Atlantic slope it was taken at several 
points in the Chagres Basin and in small coastal streams at Porto Bello 
and Toro Point. On the Pacific slope it was found everywhere, except 
in the Rio Tuyra Basin. 
After careful study of our material, together with specimens from 
Cuba and Guatemala, we find it impossible to retain the two nominal 
species, A. monticola and A. nasutus. The only reason for keeping the 
two separate heretofore apparently was the alleged difference in the 
thickness of the upper lip. We, however, find that in our large series 
this is a variable character upon which no reliance can be placed. We 
have specimens with a thin upper lip, some with a thick lip, and nearly all 
stages between. These occur indiscriminately on both slopes, and in 
the same rivers and pools. However, the thick-lipped form occurs 
more frequently among our Pacific slope specimens than among those 
from the Atlantic. 
Habitat: Mexico; Central America; both slopes of Panama and the 
West Indies. 
70. Agonostomus macracanthus Regan. 
Agonostomus macracanthus Regan, Ann. & Mag. Nat. Hist., Ser. 7, 
XIX, 1907, 65, and Biol. Cent. Amer., Pisces, 1907, 69, Pl. XI, fig. x 
(Rio Guacalate, Guatemala). 
Head 3.4 to 3.55; depth 3.1 to 3.3; D. IV-I, 8; A. II, 12; scales 41 
to 42. 
Body compressed, rather deep; head low; snout conical; 3.25 to 
3-55 in head; eye 4.34 to 4.9; interorbital 3.05 to 3.25; mouth rather 
large, slightly oblique; the upper jaw projecting; the upper lip quite 
thick; maxillary reaching nearly to vertical from middle of eye, 2.44 to 
2.6 in head; teeth as in preceding species; gill-rakers short, about 20 on 
lower limb of first arch; scales large, ctenoid, extending forward to inter- 
orbital region, about 12 rows between anterior rays of second dorsal and 
