 Abundant giant Galápagos tortoises appeared to him almost antediluvian, and large black marine iguanas seemed "most disgusting, clumsy Lizards" well suited to their habitat – he noted that someone had called them "imps of darkness".Darwin had learnt from Henslow about studying the geographical distribution of species, and particularly of linked species on oceanic islands and on nearby continents, so he endeavoured to collect plants in flower.He found widespread "wretched-looking" thin scrub thickets of only ten species, and very few insects.