Congrid Leptocephali in the Western North and Middle Pacific II. Non-Exterilium Ariosoma Type Larvae

Ariosoma type larvae with no outer-intestine of the eel family Congridae from the western North and Middle Pacific are described and figured. Five types are recorded based on total number of myomeres, position of the last vertical blood vessel in the serial number of myomere and geographical distribution. The types and their relationship with the adult are discussed. None have been certainly identified with the adult. A key is provided to the non-exterilium Ariosoma type larvae from the western North and Middle Pacific. Distribution maps showing capture locations are given for each type.