143 HYPOSTOMA DUODECIMALTS. 



along the upper margin, and which seems to be 

 a characteristic mark of the other rays of the same 

 fin. The caudal fin with the lower ray much 

 longest, the web with no sinuation. The colour of 

 this fish seems to have been of a yellowish green, 

 the lower part, or that wanting plates, of a browner 

 tint, or apparently very similar to the same part in 

 the Cotti of our British seas. 



Valenciennes has described another species under 

 the name of H. duodecimalis^ procured in the river 

 St. Francis in Brazil, and considers it identical with 

 the H. edenticulatum of Spix, and with the H. mul- 

 tlradiatiis of Dr. Hancock. We notice this, as, if 

 Valenciennes is correct, the species may be added 

 to the Guianese fishes, and is known by the pro- 

 vincial name, among the Warrau Indians, of Guasi- 

 quitu. Dr. Hancock's fish is said to frequent lakes, 

 living on the slime, and laying its eggs in holes 

 which it forms in the borders of the lakes. * 



The late volume by Valenciennes contains the 

 description of nineteen species of Hypostoma, nine 

 belonging to the ordinary form, and ten to those 

 with spined opercula. Only one in Mr. Schom- 

 burgk's Collection can be referred to any of these, 

 and we have little hesitation in adding three to the 

 list, and still less in thinking that the rivers of 

 Guiana will yet furnish a rich harvest to any one 

 who will investigate the history and habits of the 

 Loricarinae. We have noted all that is known of 

 the Jiabits of the genus we have been examining, 

 f j2ool. jJounji., iv, p. 247. 



