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CARNEGIE INSTITUTION OF WASHINGTON 
Accepting the fact of evolution, and without immediate interest in its 
mode, Dr. Boyden attempts by serological methods to determine the 
closeness of the relationship between some of the invertebrate types to 
which it has given rise. Some of the species with which he is working are 
of uncertain affinity and his findings may be awaited with interest. 
The researches of Doctors Cary, de Laubenfels, Hayes, Leitch and Stone 
and Mr. Lewis directly or indirectly deal with problems of growth and 
differentiation. 
Dr. Cary has so far been largely and successfully engaged in developing 
methods of tissue culture readily adapted to use in the ordinary marine 
laboratory. It is to be hoped he may next apply them in study of problems 
presented attractively by marine invertebrates. 
Dr. Stone, who by courtesy of the National Research Council’s Committee 
on Radiation has enjoyed the use of radium, has brought to successful 
conclusion a study continued through two seasons. He finds that the beta 
rays are chiefly responsible for the diminished powers of regeneration dis¬ 
played by the tissues of irradiated worms in his experimental cultures. 
Mr. Lewis’s attempt to discover the effect upon pigmented dermal cells 
of fishes of certain dyes known to decolorize similar cells in living tadpoles 
has perhaps failed for the moment, at least, on account of their failure to be 
absorbed. A modification of procedure may perhaps eventually open the 
way for profitable investigation of the pigmented, cancerous growths of 
fishes from this new direction. 
Dr. Manter’s study of the trematode fauna of Tortugas, in collection of 
material for which he has enjoyed the assistance of Dr. 0. L. Williams 
during the season, has progressed notably. His data promise to have much 
value not only as a contribution to systematic knowledge of a group of 
animals with respect to which much remains to be learned, but to lend 
themselves to use in a connection mentioned in last year’s report. This 
phase of his research dealing with geographical distribution is part of a 
joint investigation in which Dr. Schmitt and Dr. Longley participate. 
Cerion Breeding, by Paul Bartsch 
This year’s efforts were centered about two problems: First, an examina¬ 
tion of the existing colonies at the Tortugas, particularly the status of that 
of the first generation of hybrids between Cerion incanum and Cerion 
viaregis reported upon last year. Only five of the eight have survived. 
Secondly, the establishing of new mixed colonies of Cerion incanum and 
C. viaregis; and Cerion incanum and C. casablancce. Two such colonies, 
consisting of 500 of each species, were planted. 
One of these, Cerion incanum and C. viaregis, is placed on the south end 
of Loggerhead Key, the place being marked by a stake bearing a metal 
plate with proper legend. Another mixed colony of the same combination 
has been planted on the southwest corner of Garden Key outside of the Fort. 
Of Cerion incanum and C. casablancce a mixed colony of 500 each was 
planted near the pump house on the north side of the laboratory on Logger- 
head Key, and another of an equal number on the northwest elevated reach 
of Long Key. 
From these new colonies it is hoped to get sufficient first generation 
hybrids from which we may obtain the second generation of progeny. 
TORTUGAS LABORATORY 
281 
The second combination was made desirable because we found this cross¬ 
ing to have taken place on Bahia Honda Key last year. The status of the 
free colonies living on the various keys is satisfactory. 
The Bird Rookeries of the Tortugas 
The usual breeding colonies of sooties, noddies, common, roseate and least 
terns were present in the quarters previously occupied, but several decided 
changes in these tern colonies are to be recorded, namely, that about twenty 
pairs of the least terns were breeding on the hook at the north end of 
Loggerhead Key this year. By far the most interesting development in 
these tern colonies centers this year about Bird Key, which has again 
suffered a decided diminution from wind and weather with the result that it 
scarcely offers adequate quarters for the large number of birds that it has 
been harboring, and this has resulted in the first attempt at an exodus so 
far recorded. 
About 100 nests, probably 70 of the noddy and 30 of the sooty, were 
found on the elevated portion of Bush Key in an exceedingly retarded con¬ 
dition of development, some still containing eggs, others newly hatched 
young and the most highly advanced being less than half-grown at the end 
of our laboratory season, while on Bird Key almost all the birds were on 
wing. The noddies of this colony occupied the pads of Sesuvium, and the 
sooties, as usual, the intermediate stretches of sand. This is a very unfor¬ 
tunate selection for the first real stormy sea is sure to wash over the place. 
A better selection is that of another group of noddies, who have made about 
32 nests in the few tall bay cedars at the western end of Long Key. 
A third unfortunate choice was made by another small group of noddies 
who selected the tops of groups of massed piles on the south side of the east 
dock of Fort Jefferson on Garden Key. The young raised here when old 
enough to move about, some half-grown, had evidently fallen overboard 
and been lost. 
This restlessness on the part of the Bird Key tern colony is more than 
interesting, and it should be remembered that the sooties and noddies breed 
nowhere else in the United States. The logical key that should be selected 
by them is Loggerhead Key whose bay cedars and sandy reaches would 
furnish an ideal habitat for these birds, but here they would prove a decided 
nuisance to both our laboratory and lighthouse people, both of which are 
dependent upon rain water and cisterns for their water supply, which the 
droppings of these birds would render impossible. 
Photographs 
Time and weather permitting, 1300 feet of moving picture film were ex¬ 
posed: 300 showing the present status of the bird rookeries on Bird Key and 
the new sites chosen by the terns, and 1000 feet undersea about the Coral 
Reef. 
Serological Study of the Relationships of some Common Invertebrata, 
by Alan Boyden 
The precipitin reaction, known to possess certain advantages over other 
methods of studying systematic relationships, has heretofore been applied 
chiefly to the investigation of relationships within the Vertebrata. The 
heterogeneous assemblage of Invertebrata, whose interrelationships are 
much less certain, has scarcely been touched. The collection of materials 
to serve as antigens in such an investigation was begun at Tortugas. 
