62 



brook has one or more species, never many, and none of tnem have a 

 wide distribution. They are abundant in Lake Titicaca, and in south- 

 ern Chile are replaced by the related genus Hatcheria. 



A halfway station between the Pygidiinae with nasal barbel, free 

 gill-membranes and ordinary fish mouth and the small commensals, par- 

 asites and disreputables without nasal barbels, with narrow gill-openings 

 and inferior mouth, is found in Pareiodon. In shape and size Pareiodon 

 resembles the Havanas sold to tourists in Habana for a dollar, each one 

 put up in an individual bottle, a corkscrew furnished gratis with each 

 cigar. 



Some, at least, of the Stegophilini live in the gill-openings of other 

 fishes. The head in the species of this group is flat below, the mouth a 

 transverse slit, the teeth are minute and numerous, there is no nasal bar- 

 bel, the gill-opening is greatly restricted, the membrane being united 

 with the broad, flat isthmus. Some of them roam the billows free as 

 cats, others are known to live, occasionally at least, as commensals or 

 parasites in the gill-cavities of other fishes. Reinhardt, a Danish natur- 

 alist living for the time at Lagoa Santa, on the Rio das Velhas, a trib- 

 utary of the San Francisco, was the first one to note this fact and to 

 secure specimens. Reinhardt being told that one of the giant catfishes, 

 Psendoplatystoma cornscans, carried its young in its gills, offered a re- 



Slpgophihis inshlio.ius Reinhart. 



