EXPLANATION OF PLATE IV. 



Fig. I. — Photograph of type specimen ( 5 ) of Trygon microps. This specimen mea- 

 sured 6 ft. 6 in. across the disk. 



,, 2. — Photograph of female specimen of T. zugei, x -f^. 



,, 3. — Photograph of female specimen oi Pteroplatea zonura (considerably reduced). 



,, 4.— Photograph of young specimen of Pt. tentaculata, x c. \. A piece of white 

 paper has been placed beneath the left tentacle. 



,, 5. — Photograph of a male specimen of Aëtobatis flagelhim', x c. \. 



