1908] Davis.— Life-historii of DoJichoglossus. 217 



ABBREVIATIONS USED IN THE FIGURES. 



a. Archoiiteric cavity. 



a.m. Anlage of mesoderm. 



b.c. 1, 2, ami 3: first, second, and third body cavities respectively. 



ec. Ectoderm. 



en. Endoderm. 



ent. Enteron. 



g.e. Gland cell. 



m. Mesoderm. 



m.f. Muscle fibers. 



n. Nerve cord. 



