DR. RICHARDSON'S DESCRIPTION OF AUSTRALIAN FISH. 169 



from between the mesial ends of the coracoid bones, and its two keels converge poste- 

 riorly to terminate in a rather thin obtuse tip : to this is attached the small, hard, but 

 rather cartilaginous-looking knob which projects through the integuments. 



The dorsal spine stands on the cranium between the orbits behind a short mesial 

 crest ; it moves backwards on a small bone, itself moveable, to which the second mi- 

 nute ray belongs. This small bone must fall backwards into a pit of the interparietal 

 crest, before the spine can be made to recUne in the large furrow formed by that crest. 

 The spout-shaped interparietal crest tapers backwards to an acute point, and projects 

 nearly half its own length behind the cranium. 



There are eighteen vertebrse, the nine anterior ones having strong, but not long, 

 nearly horizontal ribs. The six first have broad triangular horizontal lateral processes ; 

 the seventh, eighth, and ninth, and five succeeding ones, have descending inferior spinous 

 processes, which interlock with the interspinous bones of the anal. The lower spinous 

 process of the fifteenth vertebra lies between the two last interspinous bones of the anal, 

 while its upper spinous process is just posterior to the dorsal fin. Three upper spinous 

 processes interpose between the cranium and the first dorsal interspinous bone. The 

 interspinous bones above and below are joined to one another by finely undulating or 

 serrated sutures, connecting the thin diaphanous plates which spring from before and 

 behind their midribs. At the bases of the dorsal and anal fins, the interspinous bones are 

 furnished with short transverse processes, giving passages between them to, and aflford- 

 ing fulcra for the muscles which move the rays. The very strong first interspinous 

 bone of the anal is sheathed laterally and before at its upper end by the descending 

 spinous processes of the seventh vertebra : its lower end dilates into a stout, flattish 

 rounded shoulder. There are three vertebrse and the interspinous bones of the caudal 

 behind the anal and dorsal fins. 



Dimensions. 



In. Lin. 

 Length from the tips of the teeth to extremity of caudal fin . .10 



Length from the tips of the teeth to base of do 8 9 



Length from the tips of the teeth to end of anal 7 6| 



Length from the tips of the teeth to end of dorsal 7 4 



Length from the tips of the teeth to beginning of anal .... 5 6^ 



Length from the tips of the teeth to anus 5 4 



Length from the tips of the teeth to beginning of second dorsal . 5 



Length from the tips of the teeth to tips of pelvic bone ... 4 8 



Length from the tips of the teeth to base of pectorals .... 3 



Length from the tips of the teeth to dorsal spine 2 10 



Length from the tips of the teeth to gill-opening 2 8 



Length from the tips of the teeth to centre of eye 2 8 



Height of body at the pelvis 4 5 



