7b Five pairs of gill openings on underside of
disc; snout length less than half disc width ............................... S
Sa Head in front of spiracles not elevated and
marked off from pectoral disc; no D ...... DASY ATIDAE (No. 30)
30
Sb Head in front of spiracles elevated and strongly
marked off from disc; a single D present .................... ............. 9
9a Head with a pair of elongated, horn or
paddle-like cephalic fins; teeth minute,
numerous and sharp, not formed into
broad crushing plates ........................... MOBULIDAE (No. 29)
29
9b Head without cephalic fins; teeth
large, few, and formed into broad
BA TOIDEA (RAYS OR BATOIDS)
crushing plates ............................. MYLIOBATIDAE (No. 2S)
28
109