HYPOSTOMA. Hi- 



but with the exception of the species which "vvas ob- 

 served to eat boiled rice, we are ignorant what is 

 their food, or the manner in which they seize it ; in 

 all those dissected, the stomach has contained either 

 nothing, or has been filled with mud. * It would 

 be curious to know, also, how the opercular spines 

 or brushes, and the strong armature, which is nearly- 

 confined in its development to the pectoral fins, are 

 employed ; and whether the conjectures which have 

 been already hazarded are in part correct. In one 

 species lately figured by D'Orbigny (If. cirrhosus, 

 Ichth. pi. 7), the snout is armed with a long tuft of 

 these spines, but which appear to have a structure 

 somewhat different. " Son museau est revetu d'une 

 peau moUe et douce qui reste lisse dans la jeune 

 age. Plustard elle se herisse de filamens charnues, 

 plus ou moins montreux, plus ou moins branchus 

 selon les individus ou meme selon les eaux ou ces 

 poissons vivent." f Are these fishes preyed upon 

 by any particular class of animals ? 



Of their anatomy we also know little, and in some 

 parts it seems peculiar. In the If. verres, Yalenc, a 

 species from Cayenne, that naturalist remarks that 

 the liver is flattened, rounded, and not large ; it is 

 placed beneath a stomach, of which the membranes 

 are very delicate, but which, when inflated, becomes 

 a large pouch, the one-half bending to pass into a 

 separate branch leading to the intestine. The ali- 

 mentary canal becomes very remarkable.and unique 

 among the Siluridse ; the diameter is very narrow, 

 * Valenciennes. + Valenc. xv. p. 312. 



