DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 173 



Colour. — The body, after maceration in spirits, has a dark clove-brown tint, a little 

 lighter and more silvery towards the belly. A moderately broad pale (yellow ?) stripe 

 commences on the chin, and keeping of the same width throughout, passes backwards 

 by the under end of the gill-opening, and upper part of the pectoral, to terminate on 

 the side over the fore-quarter of the anal fin. It is bounded beneath by a narrower, 

 greyish blue line, edged above with black, and after passing the pectoral ending in a 

 row of spots. A similar blue line commences beneath the mouth, above the yellow 

 band, and arching upwards over the cheek and through the lower third of the cheeks, 

 continues its course in a horizontal direction backwards, tapering oif, and finally ending 

 in a series of spots before it comes opposite to the termination of the yellow band. 

 These lines unite on the chin with their fellows of the other side. There are no spots 

 within the space included between the blue hnes, nor on the back before the second 

 dorsal ; but all the rest of the body and tail is ornamented with perfectly round, greyish- 

 blue pearly spots, each well defined by a dark margin. The rows of spots which run 

 along the base of the second dorsal are larger than the rest, and those on the belly are 

 smaller than those on the tail. There is a narrow vertical black bar near the end of 

 the caudal fin. 



Osteology. — Teeth above and below thin and evenly truncated at the tips, not cres- 

 centic or acuminated as in Monacanthus rudis, but otherwise similarly arranged. 

 Summit of the skull before the spine of first dorsal formed of a short mesial ridge and 

 two longer lateral ones, the intervening spaces being membranous. Structure of the 

 jaws the same as in Monacanthus rudis, the maxillary being rather more slender. The 

 cutting edges of the teeth are even, not lunated. The bones of the skull generally are 

 much more fibrous in their structure and delicate in their tissue. The broad border of 

 the preoperculum, and the two other opercular pieces are thin, diaphanous and almost 

 membranous. The styloid and pelvic bones resemble those of Monacanthus, except that 

 the small knob of the latter is retained under the integuments, and is armed exteriorly 

 by purely dermal spines. 



There are twenty vertebrae, about eight or nine of them carrying short, slender ribs. 

 The seventh vertebra receives the end of the first interspinous bone of the anal as in 

 Monacanthus rudis, but the obtuse lateral processes of that vertebra are bent downwards, 

 anterior to the interspinous bone, instead of closely sheathing it, as in the Monacanthus. 

 Some of the superior spinous processes are finely serrated. The interspinous bones 

 are joined to each other by suture as in the species just named ; and as in it, there are 

 three spinous processes before the second dorsal. The spinous processes and inter- 

 spinous bones alternate at the beginning of that fin, but the latter increase posteriorly 

 until there are four or more between each pair of interspinous bones. 



VOL. III. PART II. 2 A 



