Exotic Hydroids in the collections of the Rijksmuseum van Natuurlijke Historie and the Zoological Museum at Amsterdam

In the course of 1944, whilst engaged with the revision of the collections of Hydroids in the Rijksmuseum van Natuurlijke Historie at Leiden and the Zoological Museum at Amsterdam, I had the opportunity to study a considerable number of Hydroids from the tropical and subtropical parts of the three large oceans. No report has up to the present time been published on these Hydroids, although many specimens are of considerable interest. The present paper contains the results of the study of these samples, which were kindly put at my disposal by Prof. Dr. H. Boschma and Prof. Dr. L. F. de Beaufort. I also wish the express my sincere thanks to Mrs. W. S. S. van der Feen née van Benthem Jutting and Miss Dr. Jos. Th. Koster for their assistance in providing me with material. List of the species Tubulariidae : Tubularia larynx Ell. et Sol., 1786; Tubularia spec. Halocordylidae : Halocordyle disticha (Goldfuss, 1820) ; Halocordyle disticha (Goldfuss, 1820) var. australis (Bale, 1884). Clavidae: Cordylophora caspia (Pall., 1771); Corydendrium parasiticum (L., 1767); Campaniclava clionis Vanhöffen, 1910; Campaniclava cleodorae (Gegenbaur, 1854). Bougainvilliidae : Leuckartiara vestita (Wright, 1859) forma nana (Leloup, 1932). Eudendriidae : Eudendrium capillare Aider, 1856. Haleciidae: Halecium halecinum (L., 1758); Halecium beanii (Johnst., 1838) ; Halecium liouvillei Billard, 1934. Campanulinidae : Stegolaria geniculata (Allman, 1888). Lafoeidae : Lafoea benthophyla Ritchie, 1909 ; Hebella calcarata (L. Agas-