Contents

18 October 2019
Vol 366, Issue 6463

About The Cover

Cover image expansion

COVER A colony of the protozoan species Choanoeca flexa. As a choanoflagellate, C. flexa is one of the closest living relatives of animals. This species forms cup-shaped colonies that quickly invert their curvature in response to light-to-dark transitions by undergoing collective cell contractions. This behavior may offer insight into the evolutionary origin of tissue bending in animals. See pages 300 and 326.
Image: Thibaut Brunet (University of California Berkeley/Howards Hughes Medical Institute)