Udekem, D', on Oligochaeta, [365]

Udonella, [73];

U. caligorum, [55];

U. pollachii, eggs of, [58]

Udonellinae, [73]

Umbonula, [531]

Uncinaria, [143]

Uncinate, [210], [211]

Uncini, of Polychaeta, [266], [267], [304], [305]

Uncus, [210]