500 PROF. J. E. DUERDEN ON CRABS [ Dec. 12, 
grown Lunodeopsis fixed by its base. While walking about, the 
crab accidentally came into contact with the large Banodeopsis 
and stopped as if to examine it ; then by means of one of its first 
ambulatory limbs it began working around the base of the polyp, 
and after a few minutes detached it. At the same time it moved 
the claw holding the fragment of Bunodeopsis towards its mouth 
as if to ingest the polyp, but the fragment was merely liberated 
and left free in the dish, and the empty claw then seized upon the 
larger Lunodeopsis which it had previously dislodged from its 
substratum. The Melia had now a perfect bunodeopsid and a 
sagartiid. At a later stage the large Bunodeopsis was removed 
and the previously discarded fragment introduced into the dish, 
when after a time the latter was appropriated. 
The fragment of Bunodeopsis and also a Sagartia were again 
placed in a dish containing a Melia with both its claws unoccupied. 
These were taken up as soon as the crab came into contact with 
them, and a second perfect sagartiid was then placed in the dish. 
The crab with both its claws occupied came into contact with the 
third actinian, remained near it for some time, and then pushed it 
away. On returning fifteen minutes later, however, it was found 
that the fragment of Bwnodeopsis had disappeared, and its place was 
occupied by the sagartiid ; the J/elia had detached the bunodeopsid 
fragment and had taken up the sagartiid in its place. There 
appeared to be evidence that the crab will tear a single actinian 
in two in order to provide each claw with a polyp. 
MertHOD oF HOLDING AND SEIZING THE ACTINIANS. 
Usually the actinians were held so loosely within the chelipeds 
of the crab that the column was but slightly constricted. Asmen- 
tioned by Mobius, the joints of the chele are provided with very 
Text-fig. 75. 
Claw of Melia tessellata showing the two rows of spines. Much enlarged. 
minute spines, and these no doubt assist In maintaining the polyp 
in position (text-fig. 75). Occasionally the body of the polyp was 
held in such a manner that the column was not altogether within 
the claws, and the wall would then be constricted and indented by 
the tips of the claws. In preserved specimens the polypal tissues 
