79 
tinua, labia preorbitalia nulla. Dentes cum ossibus lunatis pre- 
maxillaribus mandibulisque, modd Scarorum ferruminati. [Ossa pha- 
ryngea ab exemplaribus nostris excisa, hinc nobis ignota.] Squame 
cyloideze. Linea lateralis simplex, e tubulis rectis facta, continua ; 
antic arcuata, posticé recta. Pinna dorsi unica, prope humerum 
incipiens, in parte spinosa, modo proprio, emarginata ; radiis spino- 
sis apicibus flexilibus. Pinnz ventrales sub axillis pectoralium po- 
site. Membrana branchiostega in gutture continua, utrinque radiis 
quatuor sustentata. 
The general form of this fish has been known to me for some years 
by the accurate drawing of Mr. Neill. It is an inhabitant of King 
George’s Sound in Australia, where it is recognised by the natives 
under the name of “ Toobitoet,” or ‘‘ Toobitooit,”’ and it is said to 
inhabit rocky places and to be rarely captured. In the construction 
of its jaws and in general form it approaches most nearly to Odaz, 
but it differs from that genus, and still more from Scarus, in the want 
of scales on the head, the single lips, and in the unusual form of the 
dorsal. The subjoined description is drawn up from a specimen pre- 
pared by Mr. Neill, which I have lately had an opportunity of in- 
specting. 
In the shape of the jaws Olisthops resembles several species of Odax 
which inhabit the Australian seas, but does not agree altogether with 
the account of the dentition of that genus as given in the ‘ Histoire 
des Poissons’ (xiv. p. 299), nor with the drawing of the jaws of Odax 
pullus (op. cit. pl. 408. f. 2). 
The jaws of Odaz, says M. Valenciennes, are composed, as in Sea- 
rus, of an assemblage of small teeth arranged in a quincuncial order 
and intimately soldered together, forming on each side a single body, 
whose cutting edge is crenulated ; but these jaws are neither so broad 
nor so convex as in Scarus, and are entirely covered by the lips. They 
differ from those of Searus in that the teeth form two spoon-bowls at 
the end of the mouth in front of the spinous pots which crown the 
teeth of the jaw. Olisthops and several Odaces want these poste- 
rior marginal toothlets, the spoon-shaped masses constituting the en- 
tire dental process of the jaw, and showing their origin merely by the 
reflections of the incorporated, minute pearly quincuncial teeth, so 
densely crowded as to form nearly the whole of their smooth exterior 
surfaces. 
OLISTHOPS CYANOMELAS, Richardson. 
Radii.—Br. 4; D. 18|10; A. 3|10; C.124; V.1[5; P. 12. 
(Pl. III. fig. 1, 2.) 
Form elongated, the greatest height of the body, which occurs just 
behind the ventrals, being contained five times and a half in the total 
length of the fish, caudal included. The bluffness of the head, pro- 
duced by the form of the jaws, is intermediate between that of Scarus 
and Odaz, and the profile, from the nostrils to the dorsal, is mode- 
rately ascending and but slightly convex. The jaws have the usual 
