yew YORK SHELL CLUB NOTES No. 245 October 1978 Page 3 
house, since special structures in the Tridacna concentrat 
sunlight on the algae and cause them to grow like the bites they 
ares Tridacna is known to use these zooanthellae as a source of 
food. 
qooanthellae are also found in some nudibranchs (P i - 
lidiella) that, however, acquired their algal 5 copy lizrhoe, Aco” | 
toelenterates that regularly possess a supply. Coral reef polyps, 
for example, need the zooanthellae to build the reefs.) It is not 
known what use the nudibranchs make of their algae. But the algae 
apparently, are none the worse for their change of residence from : 
coelenterate to opisthobranch. 
This short report does not concern itself with the mollusk-parasite 
relationship. That is another topic, only remotely related to the 
present one. 
Sources: several, but mainly J. A. Colin Nicol 
THE BIOLOGY OF MARINE ANIMALS, New York, 1960. 

DID YOU KNOW . . ABOUT FOSSIL PEARLS? 
"Some years ago, while looking over some sand (very carefully) that 
I had collected on the Chipola River in West Florida, from Oligo- 
cene strata, I found and saved a pretty little pearl. I afterwards 
found one in some Pliocene sand from California, and found one oth- 
er in some sand from Claiborne, Alabama, which I had collected from 
the Eocene. Lately, while looking over some fossils from the 
Wood's Bluff Eocene from Thomasville and Choctaw Corner, Clarke 
County, Alabama, I found one other pretty little fellow, so that 
now we have four of them here for investigation. 
Such fossil specimens may be in other museums, but I have not seen 
or heard of the fact after diligent enquiry among the wisest of our 
workers here." 
Frank Burns, Ph.D in 
NAUTILUS Vol.XI, July, 1898 
(Contributed by M. C. Teskey) 
—— 
HIGHLIGHTS OF THE JUNE MEETING 
The annual election of officers, conducted by Frank Nelson, Chairman 
of the Nominating Committee, resulted in installations as follows: 
William Walkwitz 
President 
Vice-President Fred Cannon 
Treasurer Mathilde Weingartner 
Marie Sussman 
Milton Werner 
Dorothy Janowsky, Harold Sussman, 
Nick Katsaras, William E. Old 
Retiring President Veronica Johns ceremoniously presented Dr. Walk- 
witz with the stock of NYSC stationery. ill Old, remembering that 
George Raeihle had made a gavel for presidential gratification, or 
distraction, fetched it from his office and it was later presented 
to the new incumbent, equally ceremoniously- 
The first speaker, Dorothy Jensen, offered a three-part slide show, 
Corresponding Secretary 
Recording Secretary 
Directors 
