ON A FISH OF THE FAMILY MUGILID03, 



comparison, of the mouth, &c.. of Mugil Waigiensis, which may 

 be taken as a good type of the Mugilidce. 



Fro. 2. 



a — Dentary of mandible. 



b — Premaxilla. 



c — Maxilla. 



d — Angular \ 



e — Articular / 



f— Quadrate. 



g — Interoporculum. 



of mandible. 



MSQ/KMt** 



h — Pre-operculum. 

 i— Suboperculum . 

 k — Glossohyal. 

 I — Basihyal. 

 7)i— Urohyal. 

 n— Vomer. 

 o — Branchiostegals. 



The chief and most obvious peculiarity of the fish I am 

 describing is undoubtedly the well marked division across the 

 under surface of the head, from the extremity of the ramus of 

 the mandible on one side to that of the other (shown in Fig. 1), 

 a division, however, wdrich though deep and well defined, is only 

 external, and has no communication whatever with the mouth. An 

 examination of the bones of the head (Fig, 2), shows however that 

 notwithstanding the very abnormal external appearance, the 

 actual divergence from the typical fish skull is less than might 

 have been anticipated, and in fact is not so much a divergence 

 from the type as a variation of it. 



