Ichthyological Bulletin; No. 6

Family Isuridae - This family embraces probably not more than 6 species of large swift wide-ranging sharks of the open sea, characterised by having a conical head, the snout sharply pointed, 5 wide gill-slits, vestigial spiracle, an anal fin, the caudal lunate, its axis steeply raised, the peduncle depressed and expanded to a lateral keel, the teeth powerful, triangular or lanceolate, the third upper tooth on each side smaller than its neighbours. No nictitating membrane or fin spines.Rhodes University, Grahamstown, South Afric