The Challenger
expedition of 1872–76 was a scientific exercise that made many discoveries to
lay the foundation of oceanography. The expedition was named after the mother
vessel, HMS Challenger. Prompted by Charles W. Thomson of the University of
Edinburgh, the Royal Society of London obtained the use of Challenger from the
British Royal Navy and in 1872 modified the ship for scientific work, equipping
it with laboratories, workrooms, and storage space.
To enable the ship to
probe the ocean's depths, the Challenger's guns were removed and its spars reduced to
make more space available. Laboratories, extra cabins and a special dredging
platform were installed. It was loaded with specimen jars, filled with alcohol
for preservation of samples, microscopes and chemical apparatus, trawls and
dredges, thermometers and water sampling bottles, sounding leads and devices to
collect sediment from the sea bed and great lengths of rope with which to
suspend the equipment into the ocean depths. Because of the novelty of the
expedition, some of the equipment was invented or specially modified for the
occasion. Under the scientific
supervision of Thomson, the Challenger sailed from Portsmouth, England, on 21 December 1872, and travelled nearly 70,000 nautical miles surveying and exploring the oceans.
The final results of the research were published as the "Report of the Scientific Results of the Exploring Voyage of H.M.S. Challenger during the years 1873-76". Among many other discoveries, the report catalogued over 4,000 previously unknown marine species. One of these species was the as-of-yet un-named Styela clava. William A. Herdman described and illustrated the Tunicates from the expedition publishing several reports in 1882 on simple, compound, and pelagic Tunicates.
HMS Challenger
British Natural History Collections image of the Challenger, 1872
Route of the HMS Challenger
Styela clava was collected off the coast of Japan during explorations in 1874.
Herdman noted that S.
clava appeared to be a rather common species of Styela in Japanese seas. At the
time, there were about twenty specimens of it in the British Museum collection,
which were brought to England from Japan,
and there were also some specimens from the same locality in the Liverpool Free
Public Museum. The species, however, appeared to have been never described or illustrated. The text described the characteristic features of the species and illustrations showed the external appearance and structure of the brancial sac.
Herdman wrote that the
species was club-shaped with an pyriform body supported on a stalk of variable
length that stood erect and was not
compressed. The branchial
sac of the specimens had four narrow folds upon each side. The internal longitudinal bars were numerous, about nine on a fold and twelve in the interspaces. The meshes were transversely elongated and each contained six stigmata.
Original Illustration of Styela clava
Figure 9, external appearance of 2 specimens of Syela clava, WA Herdman, 1882
Branchial Sac and Stigmata of Styela clava and several other species of Styela
Plate XIX from "Tunicata: The Report of the Voyage of the HMS Challenger".
Styela clava, Fig. 9 and 10. Figure 10, part of the branchial sac from the inside showing branchial bars and stigmata.
Wikipedia Website: Challenger expedition
National Oceanic and Atmospheric Administration (NOAA): Ocean Explorer. Then and Now: The HMS Challenger Expedition and the “Mountains of the Sea” Expedition.
University of Kansas Natural History Museum, Division of Invertebrate Zoology. Challenger Expedition (1872-1876).
Isle-of-Man Webpage: William Abbott Herdman, 1858-1924
Herdman, WA. Report of the Scientific Results of the Voyage of H.M.S. Challenger During the Years 1873-76. Zoology Part XVII. Ascidiæ Simplæ. Proceedings of the Royal Society of Edinburgh, 1882.
19thcenturyscience.org: Comprehensive Overview of the Findings of the Challenger.
19thcenturyscience.org: Tunicata: Ascidiae Simplae.
19thcenturyscience.org: Tunicata: Ascidiae Compositae.
Title Page
Styela clava, Pages 158-159
