56 
ICHTHYOLOGY 
MONACANTIIUS LESUEURII. 
Belongs, in Dr. Gunther's classification, to the same section 
as Peronii, characterised by its four-edged dorsal spine ; these 
edges being equidistant and armed with barbs. 
The body is oblong, with the upper profile of the head very 
concave ; body covered with very minute and smooth scales ; 
those of' the head and of some parts of the body are more 
granulous. The snout is thick, with its upper profile very 
convex ; its length to the anterior edge of the orbit is con- 
tained four times in the total length of the fish. The teeth 
are of moderate size, almost square, with the two upper front 
ones larger, and shaped obliquely into a point ; the ventral 
spine is of moderate size, rounded, and surrounded by a crown 
of very short spines ; it does not appear movable. The 
dorsal spine is thick, straight, and inserted over the centre of 
the orbit, which is placed obliquely ; the barbs are strong, and 
the spine is nearly as long as the snout ; the dorsal is rather 
low, and formed of thirty-four rays ; the caudal is rather long ; 
the anal has the same form as the soft dorsal, and is formed 
of thirty-three rays, and the pectorals have fifteen. 
The general colour, on the dried specimen, is a dark brown ; 
the fins have evidently been of a lighter colour, and probably 
pink. 
The total length is four inches. The specimen came from 
Western Port. 
Dedicated to Lesueur, the faithful companion of Peron, 
during their exploration of Australia in Captain Baudin's 
expedition. 
M ON ACANTHUS TROSSTJLUS. 
Alutarius)Trossulus, Rich., Ereb. & Terror, Fishes, p. 68, 
pi. 40. 
My specimen is not much over an inch and a half long, and 
the one figured by Richardson is very little larger. This sort 
can be distinguished by the broad form of its body; its 
absence of a ventral spine ; its dorsal spine rather short and 
arched, covered with short granular spines. There is no ray 
to the first dorsal, which has only the front spine. 
