24 Mr. C. T. Regan on Ihe 



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

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



when present, small, pointed 2. Sternarchidce. 



Maxillary with an apophysis articulating with a 



facet on head of vomer ; caudal tin present ; 



adipose tin represented by a long strip, lying 



in a groove on the back and attached ante- 



riorl}-^ 2 a. Sternarchinee. 



Maxillary not directly articulated with ethmoid 



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



U. Maxillaries 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 ; orbitor^pheuoid and alisphenoids well deve- 

 loped, separating parasphenoid from frontals ; 4 pectoral ladials ; 

 vertebne 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 ; vertebrae about 250. 



4. Electrophoi'ida: 



These Neotropical fishe.s 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. 



Fig. 2. 



cor 



Cleillnum and primary pectoral arch of A. Ehamphichthys rosttatus, 

 B. Sternan/iiis (dlifrons, and C. Gymnottts carajw. 



cl, cleithrum ; sc, liypcrcoracoid ; ms, mesocoracoid ; ccr, hypocoracoid ; 



r, radials. 



