Chaetognatha of the Monsoon Expedition — A lvAFJ.no 
341 
Rao (1958*, b) Rao and Ganapati (1958), 
and Ritter-Zahony (1910, 1911) records of S’. 
serratodmtafa correspond to S. paciftca . Other 
records of S. pacifica in the Indian Ocean are 
given by Tokioka (1940, 1955, 1956*, b). 
S. tasmanica populates the Atlantic and the 
southernmost part of both the Indian and Pa- 
cific oceans up to the Subtropical Convergence. 
The northern boundary follows a pattern similar 
to that of S. gazellae , although it does not pro- 
gress northward in deep layers as S. gazellae 
does. More data are needed to establish the ex- 
tension of the distribution. 
This species extends along southern Australia 
into the Pacific (Alvarino, 1964^); and it ap- 
pears from the S . tasmanica records in the Pa- 
cific and Indian oceans that the Subtropical Con- 
vergence acts as a barrier which interrupts the 
distribution of the species northward from that 
boundary. With these findings in mind, and the 
fact that this species is recorded widely in the 
Atlantic, more data are needed before definitive 
conclusions may be drawn ( Fig. 3 ) . 
Unfortunately, some of the expeditions in the 
Indian Ocean did not cover the distributional 
region of S. tasmanica, and most of the data 
from the Atlantic are difficult to interpret, be- 
cause this species has been recorded together 
with S. serratodentata under Krohn’s synonymy. 
Davids (1958, 1959) records of S. serrato- 
dentata Krohn refer probably to both S. tas- 
manica and S. pacifica and to S. tasmanica re- 
spectively. 
S. lyra, a typical Atlantic chaetognath, ap- 
peared in small numbers and only in the West- 
Central Indian waters (Fig. 3). Other records 
are given by Baldasseroni (1915), Burfield and 
Harvey (1926), Fowler (1906) as S. furcata, 
Oye (1918), Ritter-Zahony (1911), Schilp 
( 1941), and Tokioka (1956*). 
S. enflata extends along the Indian Equatorial 
waters. It is heavily distributed in the eastern 
60 ® 80 ® 100 ® 120 ® 
FIG. 3. Distribution of S. lyra and S', tasmanica in the Indian Ocean, including positive records from pre- 
vious expeditions. 
