SOUTH AMERICAN PISHES 



21 



He recorded four species of ( *oi\yiio|)()iiui hikI placed theui in 

 his Erythriniiia. They are the S/( rardia. al hi pi n n is considered be- 

 low in tlie discussion of the new subfauuly, Glandulocaudinie. 



In the last general review of the groups under consideration, 

 that of Giinther, there were thus considered a grand total of seven 

 genera and forty-three species, as compared with the fift\'-three 

 genera and two hundred and seventy-five species, known today. 



A. The Tetragonopterinae 



The Tetragonopterinae are small Characid fishes with iiighly 

 differentiated teeth in more than one row in the premaxillary, and 

 in a single, series in the dentary and sometimes in the maxillary. 

 They are scaled. The origin of the dorsal is near the middle of 

 the body. The breast is rounded, and the gill-membranes are not 

 united. There is no predorsal spine. There is usually an adipose 

 fin, sometimes not. The caudal is scaled or naked ; the anal is 

 scaled or naked ; the lateral line is complete or not ; the maxillary 

 has no teeth, or may have one or two teeth or more teeth extend- 

 ing sometimes along the entire edge of the bone ; the scales usually 

 cycloid, may be ctenoid ; the premaxillary teeth may be in two rows 

 or in three: the anal may be very short (nine) or very long (over 

 forty) ; the form may be compressed and very deep, the depth be- 

 ing equal to half the length or slender, subfusif orm ; the scales may 

 be regularly imbricate (slender species), or there may be inter- 

 polated series causing the rows to deflect toward the anal (small- 

 scaled, dee]-) species). The cheeks may be nearly naked, or the 

 second suborbital may be expanded and cover the entire cheek; 

 the ventral area may be rounded and have a distinct median series 

 of scales, or two series of scales of opposite sides may meet in the 

 center, or the ventral area may be compressed, the edges of the 

 lateral scales bent over the middle line or not ; the caudal lobes 

 may be equal, or one of them may be longer ; the teeth in the lower 

 jaw may be all alike, or abruptly minute on the sides. 



They are found everywhere from the United States to Pata- 

 gonia, and from sea level to about 11.500 feet above it. 



The genera are distinguished from each other by the various 

 combinations of the alternative characters mentioned above. It is 

 (juite certain that some of these characters have been developed 

 independently several times, so that while it is easy to define the 

 genera it is difficult to point out their inter-relationships. It is 

 also (juite certain that, since not all possible combinations have 



