− | The pupil is usually round and relatively immobile in diurnal species and is usually slit-like in nocturnal species. Geckos, such as the Tokay gecko, have a serrated pupillary opening resembling a series of small holes when the pupil is completely closed. This specificity allows for acute vision even in dim light. | + | The pupil is usually round and relatively immobile in diurnal species and is usually slit-like in nocturnal species. Geckos, such as the [[Tokay Gecko|Tokay gecko]], have a serrated pupillary opening resembling a series of small holes when the pupil is completely closed. This specificity allows for acute vision even in dim light. |