Simplify the following text for a Grade 10 native English-speaking person.
Original: In 1940 the group was reviewed in detail and every species known at the time described ( and many illustrated ) in an important monograph by Alfred Sherwood Romer and Llewellyn Price .
Simplified: In 1940 the group was reviewed in detail and every species known at the time described ( and many illustrated ) in an important monograph .