After a prolonged scrutiny of numerous colonies of Millepora in the collections of various museums I found, besides a number of colonies with open ampullae, ten specimens possessing ampullae with their coverings of a trabecular network. The chief details of these ampullae were described in a previous paper (Boschma, 1949 a). Afterwards I had the good fortune to obtain material of different species of Millepora from six localities showing ampullae in an undamaged state. These ampullae are figured and described in the present paper. I am greatly indebted to Mr. Harold Gatty of Suva, who enabled me to visit coral reefs in the Fiji Islands during the time I stayed in this locality (March, 1949). I want to thank Dr. C. H. Edmondson, curator, Bernice P. Bishop Museum, Honolulu, for a specimen collected by him on Johnston Island. I am much obliged to Dr. R. W. Hiatt, University of Hawaii, for presenting to me specimens collected by him at Bikini Island and at Yap Island. To Dr. P. Wagenaar Hummelinck, Utrecht, I owe an interesting specimen collected by him at Bonaire. I further want to thank Professor H. Graham Cannon, University of Manchester, for a specimen from the collection of the late Prof. S. J. Hickson, obtained at Brandewijnsbaai by the late Prof. Max Weber. Finally my sincerest thanks are due to Mr. A. Salverda, Groningen, who with great skill performed the difficult task of photographing of each colony a part of the surface showing numerous ampullae. As even in these excellent photographs in many cases the ampullae are not distinctly showing off against their surroundings, from each photograph a diagrammatic copy of the upper or lower third part was made. These are