Chordata Bateson, 1885 - chordates
   Class Leptocardii Müller, 1845 [monotypic] see Subphylum Cephalochordata Owen, 1846
     Order Amphioxi see Order Amphioxiformes
       1 Family Amphioxididae [monotypic] see Family Epigonichthyidae
       2 Family Branchiostomidae Bonaparte, 1841 see Family Branchiostomatidae Bonaparte, 1841
       3 Family Epigonichthyidae