Mermithidae, [150], [163]

Meromyarii, [129], [137], [142]

Mertens, on Polyclads, [6], [23]

Mesobdella, [407]

Mesocestoides, [91];

M. lineatus, life-history, [84];

specific characters, [90]

Mesonemertini, [112]

Mesostoma, [44], [45];

reproduction, [48];