EXPLANATION OF PLATE I. 



Fig. I . ^Photograph of a female specimen of the typical form of Tvygon uarnak which 

 measured 5 ft. 3 in. across the disk. 



,, 2. — Photograph of a female specimen of T. iianiak var. variegatiis which mea- 

 sured about 5 ft. across the disk. 



,, 3. — Photograph of the type specimen ( 9 ) of Trygon favus. This specimen mea- 

 sured 4 ft. 4 in. across the disk. 



