EXPLANATION OF PLATE IV. 



Fig. I. — Photograph of type specimen ( 9 ) of Trygon microps. This specimen mea- 

 sured 6 ft. 6 in. across the disk. 



,, 2. — Photograph of female specimen of T. zugei, x -i%. 



>, .3- — Photograph of female specimen oi Pteroplatea ^o^mra (considerably reduced). 



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

 paper has been placed beneath the left tentacle. 



)> 5- — Photograph of a male specimen of Aetobatis flagelhim, x c. \. 



