136 Note on the Family of Myliobatoids. 



MYLIOBATIN^E (Bon.) Ag. 



I. — Snout entire or convex in front. 



a. Teeth of the middle row of nearly uniform width before 



and behind, three to six times as w T ide as long (adult) ; in young, 



teeth of the middle row rapidly diminish in width backwards, 



where they are little or no broader than long, fide Harless. 



Myliobatis.* 

 II. — Snout emarginated in front. 



1. Teeth gradually diminishing in width towards the sides. 



Rhinoptera. 



2. Teeth like Myliobatis; the middle very wide; the 

 lateral little or no wider than long. Mylorhina. 



3. Teeth of the middle in the upper jaw narrower than 

 the internal lateral / lateral graduated towards sides. 



Micromesus. 



Holorhinus Gill. 

 Zygobatis Ag. 



Myliobatis Dum. 

 Rhinoptera Kuhl. 



Mylorhina Gill. 

 Type Rhinoptera Lalandii, M. IT., 182. 



• Micromesus Gill. 



Type Rhinoptera adspersa, M. H. 1S3. 



AETOBATINvE Ag. 

 Aetobatis M. H. 

 Goniobatis Ag. 



* According to Harless (Abli. d. Nat. Phys. Class. Bd. V., 1850), the median 

 teeth of Myliobatis aquila decrease backwards; in M. vultur, the same pecu- 

 liarity is seen. Was that fish then the young of a larger species? 



