642 Cc. H. MARTIN. 
the living condition, but in stained preparations the numerous 
proboscides seemed to resemble the proboscis of O. sertu- 
larie. 
5. Srructure OF THE VERMIFORM INDIVIDUAL. 
The fully grown vermiform individual of Ophryoden- 
dron abietinum is roughly cylindrical in shape, tapering 
somewhat towards the free distal end. ‘The stall is a solid 
rod, attached at its basal end by a slight thickening to the 
hydrotheca of the hydroid, and passing in the opposite 
direction to end in a sharp point buried in the cytoplasm 
of the Ophryodendron. During life the animal is in almost 
constant motion, swinging in various directions on its stalk. 
It is extremely difficult to make out the structure of the 
anterior end, the shape of which in the living animal is 
constantly changing. At one time the anterior end will 
show a distinct thin lip surrounding a large cavity, a little 
later this lip may be rolled back over the free surface of the 
animal, then the whole apical end may become swollen and 
the lip disappear. 
That this lip can actually exert a powerful sucking action 
is shown by some observations on vermiform individuals 
which were still attached by their basal end to their probo- 
scidiform parents. Under these conditions the vermiform 
individual would frequently attach its anterior end to the 
stalk of the hydroid and pull its parent over to one side. If 
the anterior end of the vermiform individual is carefully 
examined, a slender tube is found opening to the surface in 
the centre of the depression, and at the other end into a long 
vacuole, which in sections is seen to pass almost to the 
proximal end of the animal (text-fig. 2). 
It is possibly worth noting that the first sign of disinte- 
eration in a living proboscidiform individual is furnished by 
the appearance of drops of cytoplasm at the end of the 
tentacles, whereas in the vermiform individual a similar 
