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



base of last ray of anal; caudal fin naked, the lobes subequal; anal fin 

 rather small, its origin a little behind last ray of dorsal, about midway 

 between preopercular margin and base of caudal; ventral fins reaching 

 to or slightly past origin of anal ; pectoral fins reaching base of ventrals, 

 about as long as head without snout. 



Color silvery; sides with a plumbeous lateral band; a distinct shoulder 

 spot present; caudal spot wanting; fins unmarked. 



There are 148 specimens, ranging in length from 35 to 80 mm., in 

 the present collection. All are from the Rio Chagres and its tributaries. 

 Inhabiting upland streams where the ciu-rent is swift. 



We have compared our specimens with specimens of C. affinis 

 Steindachner, identified by Dr. Eigenmann, from Colombia and Ecua- 

 dor. We have also examined a number of the paratypes of C. magda- 

 leruB Eigenmann, and find that our specimens differ from both in having 

 I or 2 more rows of scales between the base of dorsal and base of anal. 

 Our specimens are also more slender and the upper jaw projects less 

 strongly. 



Habitat: Rio Chagres Basin, Panama. 



37. Creagrutus simus Meek & Hildebrand. 



Creagrutus simus Meek & Hildebrand, Field Mus. Nat. Hist. Pub., 



Zool. Ser., X, 1913, 85 (Rio Cupe, tributary of Rio Tuyra, 



Cituro, Panama). 



Head 3.5 to 4; depth 3.1 to 3.7; D. 10; A. 14 to 16; scales 5-34 to 36-4. 



Body elongate, moderately compressed; caudal peduncle strongly 

 compressed, its depth 2 to 2.4 in head; dorsal region little elevated; snout 

 blunt, 3.5 to 4 in head; eye 2.45 to 3.13; interorbital 2.9 to 3; upper jaw 

 notably projecting; maxillary-premaxillary border strongly curved; 

 maxillary reaching slightly past anterior margin of pupil; outer series 

 of premaxillary teeth anteriorly in advance of the lower lip, exposed 

 when the mouth is closed; maxillary with 2 or 3 small teeth; lower jaw 

 with 8 large teeth anteriorly and 3 to 5 smaller ones at sides; teeth in the 

 young tricuspid or pointed, blunt in the adult; gill-rakers short, 7 to 9 

 on lower limb of first arch; scales striate, 9 or 10 before dorsal, 7 to 9 

 between dorsal and adipose, 9 or 10 longitudinal series between base of 

 dorsal and base of anal; origin of dorsal over base of ventrals, a little 

 nearer tip of adipose than tip of snout, adipose fin well developed, over 

 base of last anal ray; caudal fin naked, the lobes subequal; anal fin 

 rather small, its origin just behind last ray of dorsal, about midway 

 between margin of opercle and base of caudal; ventral fins usually 

 reaching origin of anal; pectoral fins usually not quite reaching base of 

 ventrals, slightly longer than head without snout. 



