38 DR. MACDONALD ON A NEW GENUS OF MUGILID. (Jan. 14, 
2. On the Characters of a Type of a Proposed new Genus of 
Mugilide inhabiting the Fresh Waters of Viti Levu, 
Feejee Group; with a brief Account of the Native Mode 
of capturing it. By Jonn Denis Macponatp, M.D., 
F.R.S., Staff-Surgeon, R.N. 
(Plate I.) 
The fish forming the subject of the present paper is found in 
abundance in the deeper parts of the Wai Manu, one of the tribu- 
taries of the Rewa River, Na Viti Levu (Large Feejee). An ordinary 
specimen would measure eighteen or twenty inches from the tip of 
the snout to the emargination of the tail, and five inches vertically 
at its deepest part. ‘The native name, Ika loa (black fish), is de- 
rived from its colour, the head and upper part of the body being of 
a rich black, which gradually softens on the sides into a warm brown, 
growing paler and more silvery towards the white belly. My friend 
the Rev. Samuel Waterhouse, Wesleyan Missionary, who was with 
me when the first specimens were obtained, at once recognized the 
famous “ Black Mullet’’; but, in the absence of all works of reference, 
I was obliged to content myself with drawings and notes carefully 
taken on the spot. The more important characters of Ika loa are 
the following :— 
Head thick, convex, and rounded above, but flattened and sucker- 
like beneath, where the lower jaw is circumscribed by a thin promi- 
nent border, angularly produced in front so as to occupy a corre- 
sponding median notch in the upper lip. The eye is of moderate 
size, with a yellowish-brown iris, the snout short and bluntly pointed, 
and the mouth protrusible to a considerable extent, with the cleft on 
cach side reaching a line drawn perpendicularly through the centre of 
the orbit. The teeth of the upper jaw are minute, recurved, and 
disposed in a single series, interrupted, however, in front, where the 
lip presents the angular grooved space already noticed. Within the 
dental margin a crescentic palate-like membrane, with a transverse 
oval thickening in the middle, extends across the roof of the mouth. 
Behind this valvular membrane, and to the right and left of the 
mesial line, the vomer bears a small transverse zigzag row of teeth. 
In the lower jaw the teeth are arranged in a gently curved, villiform 
cluster on either side, with a wide median interval. A horseshoe- 
shaped series of delicate transverse sucker-like folds or plice corre- 
sponds with the contour of the mandible inferiorly, the fore part 
being very narrow, like an isthmus connecting the lateral portions, 
which gradually increase in breadth towards their posterior end. A 
similar structure is present in dgonostoma plicatile ; but the lateral 
portions are not united anteriorly as in Ika loa. This difference evi- 
dently arises, in one case, from the angular projection of the man- 
dible anteriorly, and, in the other, from its roundness at the corre- 
sponding part. 
Operculum, inter-, and preeoperculum scaly ; gill-rays six on each 
