I 



PLATE I. 



Fig. 1. Two colonies attached to a coral. Nat. size. 



Fig. 2. External surface of colony. 8/1. 



Fig. 3. Part of cross-section of colony. 15/1. 



Fief. 4- Part of longitudinal section of colony. 15/1. 



Fig. 5- Section of test. 400/1. 



Fig. 6, Branchial aperture, seen from inside. 80/1. 



