248 LIEUT. DE CRESPIGNY ON THE HABITS OF AN ACTINIA. (Apr. 8, 
the white tip to the tail and the size, the Ardennes variety being a 
much larger and stronger animal. Nilsson describes a variety very 
like the Vulpes melanogaster as inhabiting Scandinavia. 
10. Notes on the Friendship existing between the Malacopte- 
rygian Fish Premnas biaculeatus and the Actinia crassi- 
cornis. By Lieut. C. C. De Cruspicny*. 
The Anemone here spoken of is found at Labuan in various ha- 
bitats—sometimes domiciled in rows along the horizontal fissures of 
sandstone rocks (the positions being chosen so that at low water 
they may be just awash), in other cases surrounding and covering 
a mass of exposed dead madrepore. It is also found attached to 
rocks or dead coral some inches under the surface of the sand, and 
from this vantage ground protruding or withdrawing its tentacula at 
pleasure, so that when they are withdrawn the animal is no longer 
visible. On a calm evening, when the tide is out, one may observe 
with advantage the sympathy which appears to exist between this 
animal and the little fish called Premnas biaculeatus. The Actinia 
is in a state of quiescence, allowing its tentacula to float and move 
about freely in obedience to the impulse of each ripple of the water, 
they being now supple, pointed at the extremities, and gravitating 
downwards. A Premnas now passes over the Anemone, and imme- 
diately the tentacula become erect and diverge as if galvanized, while 
their extremities become clubby and phosphorescent. 
The fish hovers over it, gently rubbing the tentacula with his 
pectoral fins, and so will remain for some time. The hand-net is 
passed quietly down under the Anemone, and the alarmed fish, 
instead of swimming away, dives into the body of its friend, the 
tentacles closing over it and thus burying it in a living tomb. The 
hand of the captor now disturbs the fish in its hidden retreat, and 
upon its again rushing forth from its hiding-place the net is drawn 
to the surface of the water and the little fellow captured. The 
natural colour of this fish is pale red, having three perpendicular 
white stripes on the body. Upon its attaining full growth, however, 
when it is from four to five inches long, it becomes almost black, 
and the stripes are very nearly obliterated. In captivity I have 
known an Anemone live in perfect harmony with a Premnas for 
nearly a year. One morning the fish was found dead outside its 
tub, from which it had leapt in the night ; the Anemone sickened, 
became elongated and flaccid, and died in a few days. 
On the other hand, I have known a fish live in a tub for a long 
time without the society of its complementary Anemone. 
It may be that the fish spawns upon the Anemone, or that by 
continually rubbing its fins against the extremities of the tentacles 
it rids itself and its friend of disagreeable parasites, or that it causes 
a continuous flow of water across the body of its friend, in which 
stream are conveyed the animalcula on which it lives. 
* Communicated by E. Iliggins, Esq., F.Z.S. 
