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In Pokemon Green (the Japanese version of Pokemon Blue) the Pokémon depicted during Professor Oak's introductory lecture is a Nidorino. However, the cry that plays belongs to Nidorina. This is a mistake on part of the developers and was carried over to Blue and the localizations.

Source:
http://bulbapedia.bulbagarden.net/wiki/Pokemon_Green
http://bulbapedia.bulbagarden.net/wiki/P...e_Versions
(Both sources shows this in the triva section).