EHAMDIA. 129 



B. Width of mouth | to J the width of head. 



1. Occipital process extending ^ of the distance from its base to the origin of dorsaL 



a. Breadth of head l^ in its length, interorbital width 4 3. nicaraguensis. 



b. Breadth of head 11 to 1| in its length, interorlntal width 23- to 3^. 

 a. Pectoral spine |^ the length of head; least depth of caudal 



peduncle 3 in the length of head 4. boucardi. 



13. Pectoral spine f^ to i the length of head ; least depth of caudal 

 peduncle 1| to 2^ in the length of head. 

 * Length of snout 2? to 2J in the length of head, which is 4^ to 

 4J in the length of the fish (in specimens measuring up to 



280 mm.) 5. ■wag7ieri. 



** Length of snout 2 J to 3 in the length of head (in specimens 

 measuring up to 280 mm.). 

 Breadth of head 11 in its length, which is 4? in the length of the fish ; least 



depth of caudal peduncle If in the length of head 6. petenensis. 



Breadth of head 11- to I5 in its length, which is 3i to 4? in the length of the 



fish ; least depth of caudal peduncle 2 to 2-j in the length of head' ... 7. guatemalmsis. 



2. Occipital process extending | of the distance from its base to the origin of dorsal ; inter- 



orbital width 2f to 3i in the length of head. 

 Maxillary barbel extending to origin of adipose fin ; pectoral spine ? to \ the 



length of head 8. godmani. 



Maxillary barbel extending to middle of dorsal fin ; pectoral spine 1 the length 



of head 9. microptera. 



3. Occipital process extending \ of the distance from its base to the 



origin of dorsal ; interorbital width 4 in the length of head . . . 10. managuensis. 



II. Caudal fin with a moderately deep notch, but the middle rays more than i as long as the longest. 



A. Occipital process extending -| of the distance from its base to the origin of dorsal ; pectoral 



spine I to \ the length o£ head. 



Pectoral spine with a finely serrated inner edge and a series of antrorse denticu- 

 lations ou the outer edge ; maxillary barbel reaching origin of adipose fin 

 (in a specimen of 105 mm.) ; anal of 10 rays 11. heteracanfha. 



Pectoral spine with serrated inner and entire outer edge; maxillary barbel 

 reaching middle of base of dorsal fin (in a specimen of 115 mm.) ; anal of 

 13 rays 12. hypselura. 



B. Occipital process slender, extending \ of the distance from its base to 



the oi-igin of dorsal ; pectoral spine nearly f the length of head ; 

 maxillary barbel extending to basal part of pectoral (in specimens 

 measuring up to 190 mm.) 13. bruchjcephulu. 



C. Occipital process short, triangular, extending 1 or J- of the distance 



fi'om its base to the origin of dorsal ; pectoral spine from less thaii 

 \ to nearly | the length of head. 

 1. Humeral process not reaching middle of pectoral spine ; length of 



adipose fiu 35 to 4^ in the length of the fish ; anal of 11 or 12 rays. 14. underwoocU. 

 BIOL. CEME.-AMER., Pisces, November 1907. S 



