65 



Mv. Emery's drawing is colourcd chestnut-brou'ii, with 

 darker blotches of umber and minute specks of orange- 

 brown. The dewlap is surrounded by three rows of flax- 

 flower blue dots, behind which are three rows of brown 

 spots. The dorsal and anal have two orange-coloured 

 stripes near their edges, two rows of pale dots beneath them, 

 and three rows of brown spots towards the bases of the 

 fins. On the caudal there are three blue stripes across the 

 end of the fin, and four or five brown spotted bands be- 

 tween them and the base. In Mr. Reeves's figure of the 

 Chinese fish, the colours and aiTangement of the spots are 

 similar, though not quite the same, and there is a differ- 

 ence in the rings of colour on the caudal. The extreme 

 edge of this fin is yellow, then follow two brownish-black 

 bands, next two orange-brown ones, then two black ones, 

 succeeded again by two brown ones, and lastly two black 

 ones which are on the base of the fin. The spots on the 

 dorsal and anal are only partially shown. 



Hab. Australian seas. Port Jackson, Houtman's Abrol- 

 hos, Chinese Sea, Canton, Indian Ocean. 



MoNACANTHUS EUDis. Richardson. 



R.\Dii :— D. 



-35; A. 34; C. 12; P. 14. 



M. rudis, Richardson, Zool. Tr. iii. p. 166, An. 1841. Zool. Proceed. 

 March 10th, 1840. 



Plate XL., fig. 7, half the natural size ; 6, magnified. 



In describing this Monacanthus in the Zoological Tran- 

 sactions, I remarked its agreement in general aspect with 

 G. Forster's figure of Balistes scaber, preserved in the 

 Banksian Library, but I was deten-ed from referring it to 

 that species, because the figure showed some spinous ser- 

 ratures behind the pelvic bone on the edge of the abdomen, 

 which do not exist in the specimen of rudis, but now that 

 1 have had an opportunity of examining a greater number 

 of Australian Monacanthi, I feel more inclined than before 

 to consider rudis and scaber as one species. Forster's de- 

 scription is unfortunately mostly confined to generic cha- 

 racters, and gives little assistance in clearing up the mat- 

 ter. The only points of discrepancy that I can detect, are 

 his stating scaber to be " beaked," which rudis can scarcely 

 be said to be, and his describing the branchial opening as 

 very small and situated above the pectoral fin, whereas in 

 rudis the inferior end of the aperture descends lower in 

 front of the base of the fin than in most of the Australian 

 Monacauthi which we have seen. It ought to be stated in 

 regard to this, that in figures 1 and 3 of Plate 40, the ar- 

 tist has brought the gill-opeuings further down than they 

 actually are in the specimens. The diff"erences I have in- 

 dicated are too slight to form grounds for the establish- 

 ment of a second species, but the evil of a superfluous 

 name having been already peqjetrated, I have allowed it 

 to remain attached to a figure of the Van Diemen's Land 

 Monacautlius until specimens from Queen Charlotte's 

 Sound, New Zealand, of Forster's fish, shall place the 

 necessity of merging rudis in the prior appellation of 

 scaber beyond a doubt. 



In rudis, the profile of the face is straight or very slightly 

 convex. It reaches its summit at the dorsal spine, from 

 whence the back is horizontal to the second dorsal, and 

 then descends obliquely to the tail. The height measured 

 from the point of the pelvic bone is contained twice and a 

 half in the total length, and the thickness is equal to one- 

 third of the height. The dorsal spine stands over the pos- 

 terior half of the eye and above the gill-opening. It is 

 rounded, tapering, and acute, with a groove behind, on 

 each edge of which there is a row of spinous teeth inclined 

 downwards ; its sides are thickly studded with minute 

 rounded tubercles, and on the front are two rows of larger, 

 smooth tubercles resembling spines worn down. The trig- 

 ger ray is very short and inconspicuous. The point of the 

 pelvic bone is a small knob studded with obtuse grains ; the 

 integuments of the belly behind it, are lax enough to allow of 

 a little play, but there is no thin dewlap supported by rays 

 as in 71/. chiiiensis. The rays of all the fins are rough at 

 the base, but less so in the pectorals than in the others. 



The whole of the integument is studded with short ob- 

 tuse bristles (fig. 8), which, when examined by a lens, ajipear 

 to be ranged on the sides in short, oblique rows, five or six 

 in a row or scale, with a few solitary ones between. In some 

 places these groups are more easily made out, owing to the 

 inter\ als being wider ; but round the eye, the gill-o])enings, 

 and on the head generally, the bristles are shorter, more ob- 

 tuse, and either solitary, or so closely set, that their distri- 

 bution in separate groups or scales cannot be discerned. 

 To the naked eye, the skin appears to be finely gra- 

 nulated. 



The upper jaw is armed by ten broad chisel-shaped teeth, 

 more or less acuminated, and the posterior one on each 

 side having a thin rounded edge which overlaps the lower 

 tooth opposed to it. On the under jaw the teeth have 

 crescentic cutting edges, and are six in number. The cen- 

 tral pair, both above and below, converge at their tips. 



Forster mentions that scaber has eight teeth in each jaw, 

 and he enumerates the fin rays as follows, D.2| — 34 ; A. 34 ; 

 C. 12; P. 12. (Forster's Descript. An. p. 152). 



We have no certain information respecting the colours 

 of rudis, when recent. 



Length of the specimen, 10 inches ; height at the pelvis, 

 4*4 inches ; vertebrae, 18. 



Hab. Port Arthur, Van Diemen's Land. 



Solander describes a New Zealand Monacanthus as fol- 

 lows. " Balistes scabrosus, cinereus pintut dorsali pos- 

 teriori, pectoralibus et aiiali luteis immaculatis ; piund 

 caudali cinered in medio e virescente Jiavescenti. Pinna 

 dorsalis antica 2-radiaia, cinerea : radio postico minuto. 

 Apertura branchiarum, pallide violacea. Labium supe- 

 rius griseo-pluinbeum. Dentium maxillarum apices fus- 

 ca. Habitat in oceano Australia prope Motuaro {Norm 

 Zelandi(c)r Solander MSS. p. 36. It is noted as the 

 same with Batistes unicornu totus e cinereo plumbeus, sub- 

 tits palUdior sub-Jlavicans. Habitat in oceano prope Cap 

 Kidnappers." Solander, MSS., p. 9. These colours agree 

 with those of Forster's B. scaber as far as he has described 

 them. There are no particulars of form recorded, by 

 which we can identify Solander's fish with M. rudis. 



