75 
CHEILODACTTIiUS NIGRICANS. 
Cheilodactylus nigricans, Bichard., Proceed. Zool. Soo., 1850, 
page 63. 
Ann. and Mag. Nat. Hist., 1861, 
V. vii., p. 270. 
Gunther, Oatal., v. ii., p. 79. 
{The Butter Fish.) 
This is much more common than the other sorts on the Melbourne 
Market, and is found all the year round. The colour is of a hlueish 
grey, covered with brown spots, which on the sides take the form 
of irregular longitudinal lines ; lower parts of the body of a dirty 
white ; the head has a copper tinge on its upper part, and a gilt one 
onits sides. There are generally two brown bandsonthe operculum. 
Eye yellow ; dorsal of an obscure olive colour, spotted with brown ; 
caudal and anal similar, with a narrow terminal white edge ; 
pectorals of a dark brown ; ventrals similar, with the part nearest 
to the body becoming white. In some specimens, the colour is 
darker, but the spots always exist. It is usually about a foot 
long, but sometimes it attains twenty-six inches ; in these very 
old ones the spots on the fins often disappear, but those of the 
body are permanent. 
It is by mistake that the authors describe this fish as of an 
uniform blackish grey. 
CHEIlODACTTtrS GIBBOSUS. 
Cheilodactylus gibbosus. Bichard., Transac. Zool. Soc., v. iii., 
p. 102 ; Proceed. Zool. Soc., 1859, pi. 2, fig. 3. 
D. 18—25. C. 15. A. 3—10. P. 13. 
Height three and a-quarter times in total length ; head four 
and a-half times in same: eye three and eight- tenth times in 
length of head. The upper profile is rather short, and very 
gibbous over the head ; the mouth is extensible ; the teeth rather 
long for this genus ; the cheeks and the two opercles are covered 
with small scales. On the upper surface of the head there are 
on each side two large tubercles, the one situated over the 
anterior margin of the eye, and the other in front, just above the 
insertion of the lip. The lateral line follows the back, at about 
one-third the height of the fish at its insertion, and approximating 
