110 



NATURAL HISTORY. 



body, and is placed below the external skin. There are two other species of this genus from 

 Old Calabar, but neither of these possesses the electric organs. Even the electric species is dangerous 

 to small animals only. Its flesh is eaten, and the electric organ is esteemed by the natives for its 

 supposed healing properties, which, however, are developed by burning the tissue and allowing 

 the patient to inhale the fumes. The next group includes genera, in which the body is more or 

 less completely contained in bony armour. The males of the genus Callichthys have the spines 

 in the pectoral fins stronger and longer than those of the female, the spine increasing in size as 

 the male reaches maturity, and it is also noticed that the thoracic plates are much larger in old 

 males than in females. The species are characteristic of the rivers of tropical America and 

 Trinidad. Callichthys barbatus has the end of the snout armed with stiff bristles, and there are 

 two rows of lateral shields along each side, but behind the dorsal fin the shields of the two 

 sides join eacli other. 



Several species of Plecostomus, another genus from tropical America, have the snout armed 



LOIUCAUIA CATAPHUACTA. 



with bristles. The gemis Chsetostomus is remarkable for having the inter-operculum movable, 

 and armed with a bundle of erectile spines, which are long and bristle-like. The number of 

 spines varies in the different species, which are all from the tropical part of South America, 

 except Chfetostomus trinitatis, from Trinidad and Chsestostomus guacharote, from .Porto Rico. 



Similar spines characterise the Brazilian genera Pterygoplichthys and Acanthicus. The genus 

 Loricaria, from the fresh waters of South America, has the snout more or less elongated beyond 

 the mouth, with a short barbel at each corner of the mouth. The small bent teeth when present 

 have the apex expanded and notched. The tail is long, and flattened, and both head and body 

 are encased in armour. In the Loricai'ia cataphracta, from Siirinam and Northern Brazil., 

 the upper ray of the caudal fin is produced into an immensely long filament, a character also 

 seen in the Loricaria vetula from the Rio de la Plata, and in several other species. There are eight 

 or ten lateral scutes between the pectoral and ventral fins, and the belly and thorax are 

 defended with numerous small and irregular scutes. The outer ray of the pectoral fin is about 

 one-sixth the length of the body. The Loricaria barbata has the sides of the head armed with 

 erectile bristles. Most of the species have the snout broad, but in some it is long and narrow. 

 The Loricaria acipenserina has the snout terminating in a spiny knob, and the long snout of 



