Article: Darwin went to Edinburgh University in 1825 to study medicine. In his second year he neglected his medical studies for natural history and spent four months assisting Robert Grant's research into marine invertebrates. Grant revealed his enthusiasm for the transmutation of species, but Darwin rejected it. Starting in 1827, at Cambridge University, Darwin learnt science as natural theology from botanist John Stevens Henslow, and read Paley, John Herschel and Alexander von Humboldt. Filled with zeal for science, he studied catastrophist geology with Adam Sedgwick.

Question: Who did Darwin assist in researching marine invertebrates?
Robert Grant