Chaetognatha of the Monsoon Expedition— Alvarino 
337 
Fig. 1. Stations plan for the zooplankton collections of the Monsoon Expedition in the Indian Ocean. 
O — 1-m net 
A — mid-water trawl 
Stations corresponding to previous work in this region are: 
F — Siboga Expedition (Fowler, 1906) 
R — Gazelle Expedition, Fauna Southwestern Australia, Deutsche Siidpolar Expedition 
(Ritter-Zahony, 1909, 1910, 1911) 
B — Sealark Expedition (Burfield and Harvey, 1926) 
S — Snellius Expedition (Schilp, 1941) 
T — (Tokioka, 195 6b) 
D— (David, 1958, 1959) 
S. planctonis Steinhaus 
S. pulchra Doncaster 
S. regularis Aida 
S. robust a Doncaster 
S. tasmanica Thomson 
S. zetesios Fowler 
Seventeen of the 23 species recorded are epi- 
planktonic. Ten of these are cosmopolitan and 
seven are Indo-Pacific. Fifteen of the 17 epi- 
planktonic species in the Indian Ocean connect 
with their respective regions of distribution in 
the Pacific Ocean along the Indonesian seas. 
The mesoplanktonic species S. decipiens and S. 
zetesios apparently connect with the Pacific 
population along the same route, while S . planc- 
tonis extends into the Pacific following the 
South Australian waters. These mesoplanktonic 
species are also cosmopolitan. However, E. 
bathypelagica, obtained previously only in the 
Pacific at great depths, was recorded here once 
at the northern part of the region covered by 
the "R/V Argo” in the Indian Ocean (mid- 
water trawl no. 3, at 11° 56' 42" S — 115° 22' 
