FISH. 61 
extend as far eastward as the Keeling Islands, where Mr. Darwin’s specimen was 
obtained. 
The Sparus erythrurus of Bloch (pl. 261) is so extremely unlike the present 
species both in form and colours, that, except on the authority of MM. Cuvier 
and Valenciennes, who state that they had seen Bloch’s original specimen, no one 
could have suspected that the figure had been intended for it. 
Famity—CHETODONTID£. 
CH#TODON SETIFER. Bloch. 
Cheetodon setifer, Bloch, Ichth. pl. 425. fig. 1. 
Cuv. et Val. Hist. des Poiss. tom. vii. p. 58. 
Form.—This species is one of those characterized by a prolongation of a portion of the soft 
dorsal fin. In the present specimen it is the sixth soft ray which is thus prolonged. The total 
length of this ray, measured from the root, is half the entire length of the fish; and that 
portion of it which exceeds the adjoining rays is rather more than half. Although the 
preopercle can hardly be called denticulated, yet there are some faint traces of rudimentary 
denticulations at the lower angle. The general form, in all other respects, agrees with the 
descriptions of Cuvier and other authors. 
D. 13/24; A. 3/21; C.17, and 6 short; P. 16, the first short; V. 1/5. 
Length 6 inc. 3 lines. 
CoLour.—“ Body pale, with narrow dark straight lines which form network: across the eye a 
black band: posterior half of the body bright orange: upper part of the prolongation of the 
dorsal fin edged with black, and a round patch of the same.”—D. The black ocellus extends 
from the fifth to the thirteenth ray of the soft dorsal. There is no trace of the four red or 
yellow streaks said by Cuvier and Valenciennes to cross the forehead from eye to eye; but 
probably they are effaced by the action of the spirit. 
A second specimen only differs from the above in being smaller, measuring in length not quite five 
inches ; in having the fifth (instead of sixth) ray in the soft dorsal prolonged ; and in the 
ocellus extending from the fifth to the tenth ray only. In the last two respects it agrees better 
with the description in the ‘ Histoire des Poissons.’ The filamentous ray terminates in an 
extremely fine hair, which leads me to think that the extreme portion of this ray in the first 
specimen has been broken off. 
Habitat, Keeling Island, Indian Ocean. 
