336 Field Museum of Natural History — Zoology, Vol. X. 



anal ; origin of first dorsal about midway between tip of snout and base 

 of caudal, the first spine equal to or shorter than the second, not longer 

 than eye and snout; origin of second dorsal notably nearer origin of first 

 dorsal than base of caudal, margin of fin concave; caudal fin with small 

 scales on basal half, moderately forked; anal fin similar to second dorsal 

 but a little longer, with 2 spines, the first one minute and often hidden in 

 the skin, its origin under or slightly in advance of second dorsal, midway 

 between base of ventrals and base of caudal ; ventral fins inserted under 

 middle of pectoral, somewhat nearer origin of anal than tip of snout; 

 pectoral fins placed high, of about the same length as the ventrals, 1,4 

 to 1.65 in head. 



Color bluish black above; sides silvery, with margin of scales brown; 

 pale below. An indefinite dark lateral streak, with a silvery one above 

 it, most evident on posterior part of body; a dark caudal spot present. 

 Spines of first dorsal black, the membranes greenish; second dorsal, 

 caudal and distal half of anal dusky; ventrals and pectorals plain in 

 spirits, except that the upper ray of pectoral is black. 



There are only 2 specimens of this species in the present collection, 

 respectively 173 and 205 mm. in length. Both specimens were taken at 

 the base of a waterfall near the mouth of the Rio Indio, a tributary of 

 the Upper Chagres. 



This species differs from the preceding principally in the somewhat 

 deeper body and in the notably larger mouth. 



Habitat: Rio Guacalate, Guatemala; Rio Chagres, Panama. 



44. Genus Joturus Poey. 



Joturus Poey, Memorias, II, 1861, 263 (type Joturus pichardi Poey). 

 Xenorhynchichthys Regan, Ann. & Mag. Nat. Hist., Ser. 8, II, 1908, 461 



(type Joturus stipes Jordan & Gilbert). 



Snout protruding beyond upper lip; teeth in lower jaw in two lateral 

 patches which do not meet anteriorly; dorsal spines compressed. In 

 other respects essentially as in Agonostomus. One species known, living 

 at the foot of waterfalls and rapids. 



71. Joturus pichardi Poey. 



Joturus pichardi Poey, Memorias II, 1861, 263 (Cascades throughout 



Cuba); Jordan & Evermann, Bull. U. S. Nat. Mus., XLVII, 1896, 



821; Regan, Biol. Cent. Amer., Pisces, 1907, 70; Meek, Field Mus. 



Nat. Hist. Pub., Zool. Ser., X, 1914, 117 (both slopes of Costa Rica). 

 Agonostoma glohiceps Giinther, Ann. & Mag. Nat. Hist., Ser. 4, XIV, 



1874, 370 (Myzantla, Vera Cruz). 



