70 
FISHES. 
pectoral fins: the deep blue blotch enclosing the caudal armature is also remarkable; and the whole 
fish is more varied than as represented by Bloch and Riippel. On this account it is figured in 
the accompanying plate. 
The only anatomical notice respecting it occurs in Mr. Collie’s notes. He states that “ the 
air-bladder is very strong on the sides, so formed as to appear like white cords.” 
Monacanthus Spilosoma. 
Mon. corpore postice caudaque hispidis : lineis genarum , corporisque maculis parvis confertis seriatis, fuscis. 
D. 1,38. A. 33. C. 10. P.15. 
PLATE XXII. FIG. 1. 
Hab. apud Oahu. 
A specimen of this fish was preserved by Mr. Lay, and presented by him to the Museum of the 
Royal College of Surgeons: from this specimen, with the permission of the Board of Curators, our 
figure and description are taken. 
It is nearly smooth in front, becomes more hispid backwards, and is covered with numerous bristles 
oil the tail, the hinder bristles being hooked and directed forwards. 
The head is hollowed in its profile from the mouth to the base of the spine, which is placed over 
the back part of the orbit. Behind the spine the back is nearly straight as far as the commencement 
of the dorsal fin, along which it slopes to near the caudal. The bone representing the ventrals 
corresponds to nearly the middle of the space between the spine and the dorsal fin: the anal 
commences a little behind the point corresponding to the beginning of the dorsal. The caudal 
fin is rounded. 
The colour is pale, slightly reddish brown above, and nearly white beneath. The cheeks and 
jaws are crossed by six lines of dark brown following the direction of the outline of the lower jaw, 
and breaking after passing it into interrupted bands composed of spots of the same colour: a short 
line occurs in front of these near the mouth, and two short lines behind them under the eye. The 
markings of the body consist of numerous series of dark-brown rounded spots, so closely set as to 
occupy nearly an equal share of the surface with the ground colour. The spots towards the back are 
smaller than those of the sides, and form somewhat wavy lines : those of the sides form lines nearly 
straight: while the lines formed by the lower series of spots bend downwards, following the outline 
of the ventral surface of the fish, and making near the ventral bone an almost right angle with the lines 
descending from the head. The edge of the thin portion succeeding the ventral, is deep brown, 
slightly margined with brownish white. 
The pectoral fin is white and transparent: it appears to have been acute at its upper part. 
The dorsal and anal fins are pale, almost white, and are thickly spotted with small spots of pale 
brown ; these are most strongly marked on the dorsal. Along the base of the anal there exists an 
indication of a white line. Some of the anterior rays of the mutilated dorsal and anal fins are twice 
the length of the posterior; and both fins would appear to have sloped gradually backwards. The 
caudal fin is rounded : it is margined with deep brown : its rays are pale brown, becoming browner 
towards the tips : the membrane is milk-white, and is fringed along the edge of the rays with brown 
spots somewhat more intense than the parts of the rays to which they adjoin. 
The dorsal spine has nine acute teeth on each side, directed downwards. 
The length is four inches and a half, including the caudal fin, which is seven lines long. The 
breadth at the ventral fin is two inches ; at the commencement of the dorsal, one inch and a half: 
behind the dorsal, six lines : length of the spine, one inch : from the nose to the spine, one inch one 
line : from the spine to the commencement of the dorsal, one inch three lines. 
The teeth are ovate at their tips, which are yellowish brown. 
We know no species of Monacanthus approaching the present in marking. M. Cuvier has indi- 
cated one under the name of guttatus, but has not described it ; and we are consequently unable to 
determine what relation it may bear to the one before us. 
