194 Herbert W. Rand 
actinians which occur about the Bermuda Islands. The many 
crevices and miniature caverns in the soft calcareous rock between 
tide levels house myriads of beautifully colored anemones. Of 
various sizes, some of the larger of them, when seen expanded in 
the water, appear as big as a man’s head, and the extended ten- 
tacles have in general the dimensions of good sized earthworms. 
In one of these large tentacles we have essentially the same struc- 
ture as in Hydra—the typical ccelenterate condition. But the 
gastro-vascular cavity has enormously greater cross-section both 
absolutely and relative to the thickness of its wall. Further, there 
is much higher differentiation of muscle fibers. 
The experiments which I am about to describe were carried 
out at the Bermuda Biological Station for Research in the sum- 
mer of 1907. Some supplementary observations were made at 
the same place in the summer of 1908. The subject of most of the 
experiments was Condylactis passiflora (for a description of the 
species see McMurrich, ’89), the largest and most gorgeously col- 
ored of the Bermuda actinians. Most of the experiments were 
repeated upon a member of the genus Aiptasia. 1 was unable to 
identify the species to a certainty, although it agreed fairly well 
with McMurrich’s description of Aiptasia annulata. Condylactis 
occurs in great abundance about Agar’s Island, upon which the 
Biological Station is situated. Comparatively small individuals 
were selected for experiment, as being more conveniently main- 
tained in healthy condition in small aquaria. Individuals under 
experiment were kept in large glass vessels of sea water, which 
was changed twice daily. “They were fed small pieces of raw fish, 
usually once a day. ‘Treated in this way they remained in good 
condition, so far as I could judge, for ten days—the longest period 
during which any one: individual was kept under observation. 
DESCRIPTION OF EXPERIMENTS 
An individual of Condylactis which furnished tentacles for 
several experiments had the following dimensions when well 
extended.—Height of column, 75 mm.; diameter of disc, 60 mm.; 
length of the larger tenta¢les, 70 to 80 mm.; diameter of these 
