Читать книгу Clinical Guide to Fish Medicine - Группа авторов - Страница 78

There have two dorsal fins and an anal fin. Five gill slits are present that are broad and extend beyond the base of the pectoral fin. Sand tiger sharks (Carcharias taurus) differ in that the gills are in front of the pectoral fin. Spiracles are present behind the eyes but are small. The eyes lack a nictitating membrane. The mouth extends behind the eyes. They have a ring‐type spiral intestine. This group is unique in its practice of oophagy or adelphotrophy (uterine cannibalism) (Nelson et al. 2016). Some members of this group practice endothermy, e.g. white (Carcharodon carcharias) and mako sharks (Isurus spp.).