EXPLANATION OF PLATE II. 

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



la. — Trygon uarnak (3'oung). Scale 



-Trygon gerrardii (adult female). Scale 



1 



6- 



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



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



4. — -Head of Myliobatis nieuhofii var. cornifera (nat. size). 



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



