24 



]\Ir. C. T. Reo-an on the 



B. No mesocoracoid ; lower limb of liypocoracoid ending at edge of 

 cleithrum far above the symphysis; air-bladder free; teeth, 

 when present, small, pointed 2. Sternarchidce. 



Maxillary with an apophysis articulating with a 

 facet on head of vomer ; caudal fin present ; 

 adipose fin represented by a long strip, lying 

 in a groove on the back and attached ante- 

 riorly 2 a. Sternarchince. 



Maxillary not directly articulated with ethmoid 



or vomer ; no caudal ; no adipose tin 2 6. SternopygincB. 



II. Maxiliaries very small. Hypocoracoid a small lamina ; meso- 

 coracoid present, but very small ; lowest pectoral radial shorter 

 than the next. Anterior nostril labial; vent jugular; mouth 

 moderate ; teeth in jaws strong, uniserial ; palate toothless. No 

 caudal ; no adipose tin. 



A. Body scaly, compressed, moderately elongate ; no electric organs ; 



a small fontanel; orbitosphenoid and alisphenoids well deve- 

 loped, separating parasphenoid from frontals ; 4 pectoral ladials ; 

 vertebrae about 120 3. Gymnotidce. 



B. Body naked, not compressed, very elongate ; large electric organs 



in the tail ; no fontanel ; orbitosphenoid and alisphenoids appa- 

 rently suppressed, the parasphenoid extending upwards to the 

 frontals ; 7 or 8 pectoral radials ; vertebrje about 250. 



4. Electrophorid<p. 



Tliese Neotropical fishes have usually been placed in a 

 single family, but I think that it will be readily admitted 

 that the remarkable differences indicated above call for the 

 recognition of at least four families. 



Fiff. 2. 



Cleithrum and primary pectoral arch of A. Bhamphichthys rostratm, 

 B. Sternarchus alhifrons, and C. Gymnotus carapo. 



cZ, cleithrum ; sc, hypercoracoid ; »?s, mesocoracoid; cor, hypocoracoid j 



r, radials. 



