Basic shape for iota mouth , thin neck , vertical abdomen , ring foot .
康塞尔又说：第二目是腹鳍鱼，腹鳍是垂在肚腹下面和在胸绪后边，而不是长在肩骨上；
Secundo , Conseil went on , the abdominals , whose pelvic fins hang under the abdomen to the rear of the pectorals but aren 't attached to the shoulder bone ,
垂腹