EXPLANATION OF PLATE II. 



Fig. I. — -Trygon uarnak var. variegatus (adult female). Scale about -^--. 

 la. — Trygon uarnak (young). Scale ^. 

 2.— Trygon gerrardii (adult female). Scale \. 



3. — Denticles on upper surface of tail of Trygon microps (nat. size). 

 3«. — Denticles on centre of back of same species, x 2. 

 4.^ — ^Head of Myliohatis nieuhofii var. cornifera (nat. size). 

 4«. — Denticles on back of same species, much enlarged. 



