60 ZOOLOGY OF THE VOYAGE OF THE BEAGLE. 
to form a point backwards. Caudal forked nearly to its base; the lobes much elongated ; the 
upper one, which is a trifle longer than the lower, contained rather more than three times and a 
half in the entire length. Pectorals narrow and pointed, a little shorter than the head, and 
contained not quite four times and a half in the entire length; fifth and sixth rays longest. 
Ventrals attached a little behind the pectorals, and not much more than half their length ; the 
spine about three-fourths the length of the soft rays, and scarcely stouter than the third spine 
in the anal: the axillary elongated scale three-fourths the length of the spine. The scales on 
the body of this species are not materially different from those of the G. Plumieri described in 
the “ Histoire des Poissons.” . 
B63 (Di G0 eA. Siz Oils) Sco. LO. Vie Lie 
Length 7 inches. 
CoLour.—“ White, silvery.”—D. The fins are yellowish; the membranes here and there dotted 
with black : the lobes of the caudal are bordered internally with dusky. I see no trace of the 
interrupted longitudinal bands spoken of by Cuvier and Valenciennes, neither is there any 
allusion to them in Mr. Darwin’s notes taken from the recent fish. 
Habitat, Keeling Island, Indian Ocean. 
I do not feel confident as to this species being, any more than the last, 
identical with that to which I have referred it. It requires an inspection of a 
large number of specimens in order to ascertain the true value of characters. 
The present one agrees with what is stated of the G. Oyena by Cuvier and 
Valenciennes, excepting that the second anal spine, which they represent as 
shorter than the second dorsal spine by one-half, is here shorter by one-third only : 
also, as mentioned above, there is no appearance of any longitudinal bands. 
There is no other species in the “ Histoire des Poissons,” to which it approaches 
more closely. But comparing it with Riippell’s figure, if this last be scrupulously 
exact, there are a few other differences besides those already alluded to. Thus 
the first anal spine in Mr. Darwin’s specimen appears shorter in relation to the 
second, and this last stouter as well as longer. Also the soft rays of this fin 
gradually decrease, giving a sloping direction to the margin, whereas in Riippell’s 
figure, all the rays are nearly of the same length, and made equal to the second 
and third spines. The caudal lobes, likewise, appear longer in Mr. Darwin’s 
specimen. It must be left for others to determine whether these discrepancies 
are indicative of a specific difference or not. As regards the geographic range of 
the G. Oyena, 1 know not that there is any thing in this respect to render its 
identity with the species here described improbable. It inhabits the Red Sea ; 
and is also said to be common at the Mauritius ;—whence it may very possibly 
