22 ON THE SPECIES OF TFIE GENUS ANOSTOMUS. 
Lake Hyanuaiy, Lake Saraca, Manacapouru, Manaos, 
Obydos, Eio Puty, San Paolo, Serpa, Tabatinga, Teffe, 
Toiiantiiis, Villa Bella. 
Anostomus dissimilis, sp. n. 
D. 12 ; A. 11 ; V. 9 ; L.l. 43-45 ; L. tr. JL. 
4(5) 
Nearly related to both of the preceding. Darker in 
color than A. fasciaius, and distinguished from it, as from 
A. viUatus, by the absence of a spot on the base of the 
tail. The blotches on the flanks vary greatly, being re- 
duced, irregular, faint, or entirely absent. Length of 
head equal to the depth of body and contained in total 
length, without caudal, four and two-thirds times. The 
mouth opens forward, the lower jaw is very little the 
longer, the teeth are all crenulated. Twelve specimens 
from the Rio Puty. 
Anostomus isognathus Kn. ; Gth. 
A. Knerii St. 
The lateral band, figured by Kner, appears to be quite 
variable. Specimens from the Velhas show it still further 
reduced than in the form figured as A. Knerii, it being 
simply a black spot at the base of the caudal with faint 
indications of continuation forward and backward. There 
are five entire series between the lateral line and the ven- 
tral, or seven between the line and the median ventral se- 
ries. Mouth directed forward, jaws nearly equal, teeth 
crenulate in the upper and lower. Snout about one and 
one-half times as long as the eye. Depth three and two- 
thirds and leno-th of head four and one-fourth times in the 
total length, without caudal. The row of scales from the 
first ray of the ventral toward the hinder part of the dor- 
sal passes entirely behind the latter. 
