INTRODUCTION The present report deals with a collection of Hydroids from the Zoological Museum, Munich, German Federal Republic (Zoologische Sammlung des Bayerischen Staates, München), collected during various expeditions in the Caribbean region. I have thought it advisable to include in this report an annotated checklist of all Hydroids that in the course of time have been recorded from the Caribbean region. The geographical boundaries of that region are discussed below. I want to express my sincere gratitude to Dr. W. Engelhardt and Dr. H. Fechter of the Zoological Museum, Munich, who have placed the valuable material at my disposal. All the material is now preserved in the Zoological Museum, Munich; some duplicates are present in the collections of the Rijksmuseum van Natuurlijke Historie, Leiden, The Netherlands. LIST OF THE SPECIES Family Halocordylidae. — Halocordyle disticha (Goldfuss, 1820). Family Clavidae. — Turritopsis nutricula (McCrady, 1856). Family Bougainvilliidae. — Garveia humilis (Allman, 1877). Family Eudendriidae. — Eudendrium carneum Clarke, 1882. Family Haleciidae. — Halecium reflexum Stechow, 1919. Family Campanulariidae. — Campanularia (Clytia) noliformis McCrady, 1858; Campanularia (Clytia) cylindrica (L. Agassis, 1862) ; Laomedea (Phialidium) pelagica (Van Breemen, 1905) ; Laomedea (Phialidium) tottoni Leloup, 1935 ; Laomedea (Obelia) bicuspidata (Clarke, 1875) ; Laomedea (Obelia) longicyatha (Allman, 1877) ; Laomedea (Obelia) congdoni Hargitt, 1909. Family Campanulinidae. — Cuspidella humilis Hincks, 1866.