Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to

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The larger thecate hydroid species of Indonesia
are relatively well known, mostly through the
studies of Billard (see below). The medusae of
the region are also quite well known, except
perhaps the smaller forms (Kramp 1968). In contrast,
the athecate hydroids and smaller thecate
hydroids producing medusae are very poorly
known. These forms can often not be identified in
dredged material because they require live observation
and knowledge of the complete life-cycle.
The first study dealing exclusively with Indonesian
hydroids was by Pictet (1893). It was based
on material collected by M. Bedot and C. Pictet
during an expedition to the Moluccas (Bedot
1893–1909). Shortly afterwards, this publication
was followed by the studies of von
Campenhausen (1896) and Weltner (1900). The
Dutch Siboga expedition in 1899–1900 produced
a particularly rich collection of hydroids
studied thoroughly by Billard (1911a through
1942b). The investigation on the Stylasteridae of
the Siboga expedition was published by Hickson
& England (1906). Also Stechow & Müller
(1923), Leloup (1930), Vervoort (1941), Cairns
(1983), and Vervoort (1993) contributed important
accounts on Indonesian hydroids (see Appendix
2). For the hydromedusae, the synopsis of
Kramp (1965, 1968) remains certainly the most
relevant publication. A newer account is provided
by van der Spoel & Bleeker (1988). Because
the hydrozoan fauna of the tropical Indo-
Pacific is rather homogeneous and certainly belongs
to one biogeographic unit, systematic studies
from waters belonging to other economic
zones often contain essential information. The
most important of these studies are: Allman
(1883, 1888), Bale (1884), Thornely (1900,
1904), Nutting (1905, 1927), Jarvis (1922),
Millard & Bouillon (1973), Vervoort & Vasseur
(1977), Bouillon (1978a, 1978b, 1980, 1984b,
1985b), Gravier-Bonnet (1979), Watson (1985,
1997, 1999, 2000), Rees & Vervoort (1987),
Gibbons & Ryland (1989), and Ryland & Gibbons
(1991).
The present account deals with hydrozoan
polyps collected by Mortensen’s Kei Island Expedition
as well as the hydroid material described
by Pictet (1893). The numerous new records
demonstrate that our knowledge of this region is
still far from being complete.
P. SCHUCHERT
MATERIALS AND METHODS
Materials
The hydroids of the Danish expedition to the Kei
Islands are kept by the Zoological Museum, University
of Copenhagen. Some slide material of
this collection as well as some alcohol material of
species collected in great abundance are also in
the Natural History Museum of Geneva. The
localities are given – if available – as Kei Islands
Expedition station numbers. The geographic coordinates
and further data of these stations are
given in Appendix 1 and in Mortensen (1923).
Some material of the Kei Islands Expedition was
taken at sites without a station number and therefore
the information on the labels is given here.
The specimens were examined with a dissecting
microscope or a compound microscope using
temporary or permanent preparations on microscope
slides (see Gibbons & Ryland 1989).
Drawings based on material examined for this
study were usually made with the help of a camera
lucida. The figures given in this publication
thus enable calculation of linear dimensions. In
cases where a species was recorded from one
station only, no locality data are specified in the
legends of the illustrations.
Taxonomy and technical terms
Supraspecific taxa are here used as defined in
Cornelius (1995a, 1995b), Bouillon (1985a), or
Millard (1975), except for the Hydractiniidae and
Cordylophoridae, which are delimited as discussed
in Schuchert (2001). Additionally, the
families Tubidendridae Nutting, 1905 and Hebellidae
Fraser, 1912 are here regarded as valid.
Technical terms are generally used as explained
in Cornelius (1995a, 1995b), Millard
(1975), and Schuchert (1996, 1997).
Abbreviations
MHNG Muséum d’Histoire Naturelle, Geneva,
Switzerland
NMNH National Museum of Natural History,
Smithsonian Institution, Washington
D.C., USA
ZMUC Zoological Museum of the University
of Copenhagen, Denmark