Hydroids from the Theta, Vema and Yelcho cruises of the Lamont-Doherty geological observatory

Abstract

The material reported upon below was received in 1968 from the America n Museum of Natural History, New York, U.S.A., and constisted of 124 lot s of unidentified hydroids, the majority of which originated from the con -tinental shelf bordering the Atlantic coasts of the American continent. A ver y significant part of the collection comprises material from localities alon g the Atlantic coast of southern Argentina, the Estrecho de Magellanes an d Tierra del Fuego, an area of great zoogeographical interest and with a badl y known though richly developed hydroid fauna. The hydroid material in th e present collection in many instances consisted of small fragments or had bee n badly compressed, so that a fairly high percentage Gould not properly b e identified. The localities, with some exceptions, are widely spaced, rangin g from the deep sea to a few metres depth. I do not feel justified, therefore , to draw more than a few very tentative zoogeographical conclusions, expectin g that the extension of the distributional range of certain species recorde d below can later on be used when a more complete survey of the hydroi d fauna of the southern part of South America is undertaken, preferabl y including material from more Pacific localities than at present I have a t my disposal .