Needles for dissecting, [61]

Nervous system, [44]

Nycteribia, [26]

Ogata, [87]

Orthoptera, [34]

Otospermophilus beecheyi, [98]

Oudemans, his classification, [110]

Ovaries, [51]

Oviedo, [74], [76]

Palæopsylla, [19]