STDDIES IV ACSTRAMAN FISIIKS McCTM.OCH. 125 



have been observed to cast a gleam of liglit ahead fVom each niaudibular 

 Inmiuoiis organ, which circumstance has earned foi' tlie species the popular 

 title of " Port and Starboard Light Fish." 



\^iirl((tioti. — Six specimens 1-45-210 mm. long, from New South Wales 

 and two from Western Australia exhibit variation in the numbei- of scutes, 

 those from the east liaving fourteen to fifteen in a row from the slioulder 

 to tlie base of tlie tail while the western examples have tliii-teen to fourteen. 

 The dorsal spines of tlie western specimens are smaller than those of the 

 east, but as tlie specimens are npparently similar in all structural details, 

 it is probable that they are referable to the one species. 



Localities. — New South Wales coast, and Fremantle, Western 

 Australia. 



Family MUGILID^. 



Genus MuGir,, LlvintPiift. 



Through the kindness of the Director of the Queensland Museum, I 

 have been able to examine the holotypes of some of Ogilby's species of 

 this genus, and to compare them with allied species. The following key 

 indicates their relationship and tlieii' principal distinguishing characters. 



'(. An anterior ami posterior eyelid. 



b. 8 anal rays ; about 4fl scales between operculum and hypuial 



joint flohiilu. 



Lb. 9 anal rays ; 29-34 scales between oi)erculum and hypural joint. 



c. End of mandible exposed when the mouth is closed ; pectoral 

 fin shorter than or equal to distance between the oper- 

 cular margin and the anterior orbital edge. No distinct 

 dark axillary spot. 



iJ. About 30 scales between operculum and hypural joint. 



e. First dorsal spine reaching more than half its distance 



from base of last dorsal ray dussninieri. 



ee. First dorsal spine not reaching lialf its distance from 

 base of last dorsal ray. Dorsal and anal fins almost 

 completely covered with scales taJoi-iis. 



cc. End of mandiV>le ahuost or entirely hidden below the pre- 

 orbital when the mouth is closed. Pectoral at least as 

 long as the space between o ercnlar edge and anterior 

 margin of orbit. A pronounced dark axillary spot. 



/'. Cheek-scales finely ctenoid ; 30-32 scales between operculum 

 and hyijural joint. Body-scales without distinct mem- 

 branous borders. Their surface sculpture being continued 

 to the edge. Dorsal and anal rays not hid<len by scales. 

 First dorsal spine nearer tlie hypural joint than the end 

 of the snout ..georgii. 



ff. Clieek-scales cycloid ; 33-3i scales between the operculum 

 and the hypural joint. Each body-scale with a mem- 

 branous border which is not sculptured like tlie surface 

 of tl;e scale. Dorsal and anal rays largely hidden by 

 scales. First dorsal spine nearer the end of the snout 

 than the hypural joint longimanus. 



