nz a JTRSUEIA VOL, eos 
between 2421 SCA (TMR TS NS DON Em) rand rss ACH (Oe is aS 
p.m.). The latter temperature however was observed in a little deserted 
pond, only a few square metres in extent, hardly more than one foot deep, 
and for the greater part choked with Najas falciculata R. BR.. 
The two other temperatures also observed on March 19th 1918, at 1.30 
p.m., and those observed on May 14th 1918, at 1 p. m., and on October 28th 
1918, at 1.20 p. m., of respectively 34°.9 and 35°.3 ; 35°.1 and 37°.1 ; and in the 
third place 34°.4 C., all refer to fairly normal ponds that were in use, near 
Heemraad Oost, which are not, however, among the largest and deepest 
ponds in the Batavia fish-pond belt. The temperature of 36.1 degrees Celsius, 
observed on October 15th 1918, at half past twelve in the afternoon belongs 
also to a normal pond near Luar Batang on the Muara Baru. 
CHAPTER IV. 
The submerged vegetation in the Batavia empangs. 
The photos no. 2, 3, 4, 6, 8, 9, 14 and 15 (Plates 
VII, VIE, IX, XI, XIV, XV, XXII and XXIII) present a 
picture of the submerged vegetation reaching up to just 
beneath the surface of the water and developing spontane- 
ously in the Batavia empangs; as we shall see in Chapter 
V this vegetation serves for food to the bandeng-fish 
(Chanos chanos (FORSK.)) reared in those empangs. 
Of the plant-species composing this vegetation the 
principal one is a filamentous alga usually called 
“umut kan) (fras-alo a) or Bm Stu 
(“silk-alga”) at Batavia. 
Dr. W. M. DOCTERS VAN LEEUWEN, the Director 
of the Botanical Gardens at Buitenzorg, sent a sample 
of this lumut sutra for determination to Mrs. A. WEBER 
_ — VAN BOSSE. The alga proved to be a species of 
Fig. 1. Extremity of a Chaetomorpha *) (Chlorophyceae, Siphonocladiales, 
Chaetomorpha-filament Cjadophoraceae), and according to Mrs. WEBER in 
from the Batavia empangs Ee : ; 
with rhizoids (?) X 70. all probability Chaetomorpha herbipolensis LAGERH.. 
Mrs. WEBER however, added that not having seen 
a basal cell with which the filaments are fixed to the substratum 
1) Personally I had taken lumut kain to be an alga belonging to the Chaetophorales 
(= Confervales) and more particularly to the Ulotrichaceae. 
Dr. CH. BERNARD to whom I forwarded a sample of lumut kain was inclined to share 
this view, adding however, that he had found that of the known Ulotrichaceae, none 
but the genus Microspora can possess such netlike chromatophores (as visible in the 
lumut kain) but that he was unable to assert whether the lumut kain ought really to 
be looked upon as a Microspora species. In connection herewith, when meaning lumut 
kain, I used (%) to refer to it as the “Microsporalike alga”, 
