18 EDIBLE FISHES OF XEW SOUTH WALES. 



readies to tlie hinder margin of the eye or even beyond it. Opercle with 

 two concealed spines, the lower much the longer and more acute. Teeth in 

 the jaws villiform, witli the outer series slightly enlarged ; vomerine teeth 

 in a triangular, palatine in a lanceolate patch. The dorsal fin commences 

 at a considerable distance behind the base of the pectoral, and extends 

 backwards a little further than the anal ; the spines are strong, the fourth, 

 fifth, and sixth subequal and longest, 3'33-3'90 in the length of the head, and 

 much shorter than the rays ; the last spine is about equal in height to the 

 second, and five eighths of the longest spine ; the base of the rayed dorsal is 

 five sevenths of that of the spinous, and its outer margin, as is also that of 

 the anal, is rounded : the anal fin commences beneath the first or second 

 dorsal ray ; the spines are short and stout, the third usually a little longer 

 than the second, its length 4-60-5-00 in that of the head, and 2-00-2-33 in 

 that of the longest ray : ventral small, the outer ray with a short filament, 

 its length from 2-00-2-40 in that of the head, and 2-U0-2-25 in the distance 

 between its origin and the vent ; the spine is short and weak, equal in length 

 to the last dorsal spine : pectoral short and rounded, its length 2 '00-2 '33 in 

 that of the head : caudal rounded, the pedicle deep and strong, its least 

 height 2 '33-2 50 in the height of the body. Scales small and cj'clid, the 

 vertical fins scaly to about half their height. 



Colors. — Olive green above, with numerous small darker spots ; below 

 white or pale yellow : soft dorsal, anal, and caudal fins with or without pale 

 margins. 



Castelnau's Oligorus mitcJielli, which, is said to differ from O. macquariensis 

 in having a much broader head, larger eye, the npper jaw longer than the 

 lower, the operculum more rounded, the caudal fin a little longer, and the 

 height of the body much greater, is without doubt identical with the species 

 above described ; the size of the eye depends entirely on the age and length 

 of the individual, a specimen six and a half inches in length having the eye 

 as much as four and one third in the length of the head, while in one of 

 twenty inches the proportion is one seventh, as given in the British Museum 

 Catalogue, and in very large and old examples would doubtless be considerably 

 less. With regax'd to the comparative length of the jaws much variation 

 appears to exist; the authors of the " Histoire JSTaturelle des Poissous" 

 state that the upper jaw is the longer {c'est j)hd6t sa maclioire superieure 

 qui depasse Vautre), thus agreeing in this respect with Castelnau ; 

 Glinther giv'^es the lower jaw as the longer, but in the five specimens 

 examined in the preparation of the above description, the jaws were abso- 

 lutely equal, while the figure in the study of fishes shows the upper jaw 

 distinctly the longer, and may possibly, therefore, have been drawn from a- 

 specimen belonging to Castelnau's supposed form. The length of the caudal 

 fin also varies, not only with the age of the fish, being proportionately 

 shorter in large examples, but also with relation to the conditions surrounding 

 the individual ; for instance, those residing in lakes or sluggish creeks and 

 lagunes, would naturally have a less developed caudal fin than those which 

 habitually dwell in swift ilowing streams, where a greater expenditure of 

 muscular energy would be necessary to keep them in position against the 

 current. The increased height of the body is obviously due to the condition 

 of the ovaries, but iu no case has a specimen come under our notice in which 

 the proportion was so large as four times and a half in the length icifhouf the 

 caudal, as mentioned by Castelnau, for presumedly the normal proportion ; 

 such, indeed, is unusual, even Avhen the caudal fin is included, and only 

 occurs in very young or diseased fishes, or immediately after the deposition 

 of the ova ; in a normally developed fifteen inches iish now before us, the 



