362 
THE VOYAGE OF H.M.S. CHALLENGER. 
These lists seem to indicate that Compound Ascidians are very much more 
abundant at some localities {e.g., Simon’s Bay, Kerguelen Island, Station 162, Station 
313) than at others; but it must be noted that in the case of Kerguelen Island the 
length of the list is due, to a certain extent, to the very considerable time (several 
weeks) spent by the Expedition in investigating that region. Some areas in the above 
list, however, in which there were a large number of observing Stations, show singularly 
few Compound Ascidians. For example, no specimens were obtained in the South 
Atlantic between Bahia and Simon’s Bay (see the Map, where the red circles indicate 
the Stations at which Simple or Compound Ascidians were found), only a single species 
was obtained in the South Pacific Ocean, and none in the North Pacific. On the 
other hand, some of the more limited areas have long lists of species ; for example, 
twenty-one species were found in the immediate neighbourhood of Kerguelen Island, 
nine species on the south-eastern coast of Australia, and fourteen species in the Strait of 
Magellan. 
In the table given below, the geographical regions already made use of have been 
grouped together to form seven great areas,^ namely : — 
(1) The North Atlantic, 
(2) The South Atlantic, 
(3) The Southern Ocean (the region lying to the south of the Indian Ocean, and 
including Kerguelen Island), 
(4) The seas of the Malay Archipelago (the area lying between Australia and 
China), 
(5) The North Pacific, 
(6) The South Pacific, and 
(7) The shores of the southern end of South America from Valparaiso on the west 
coast to Monte Video on the east. 
This last named area has been separated from the South Atlantic and the South 
Pacific Oceans, to which its eastern and its western parts should respectively belong, 
because of the large number of Compound Ascidians which were found on the Pata- 
gonian coasts, and the difficulty of dividing them naturally into an east coast and 
a west coast series. 
As the species arc arranged in systematic order, this table shows at a glance the 
distribution of any particular species, genus, or family in the great ocean basins, according 
to the Challenger investigations. 
' Indicated Ly the red numbers 1 to 7 in the map at the end of the Eeport. 
