Life cycle and early development of the thecosomatous pteropod Limacina retroversa in the Gulf of Maine, including the effect of elevated CO 2 levels Ali A. Thabet ab , Amy E. Maas ac* , Gareth L. Lawson a and Ann M. Tarrant a a. Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543 b. Zoology Dept., Faculty of Science, Al-Azhar University in Assiut, Assiut, Egypt. c. Bermuda Institute of Ocean Sciences, St. George’s GE01, Bermuda *Corresponding Author, equal contribution with lead author Email: amy.maas@bios.edu Phone: 441-297-1880 x131 Keywords: mollusc, ocean acidification, calcification, mortality, developmental delay