70 
SHELL GALLERY. 
Fig. 20. 
Tubulipora flabellaris. 
i, half of an incrusting colony, x 8 ; 6, a few cells, x 44 ; c, a'colony, 
natural size. 
Table 
Case A, 
upright 
part. 
Order II. — Phylactol^emata. 
All the forms in this group inhabit fresh water, where, in the 
form of creeping or erect branching growths or masses, they grow 
attached to fresh-water plants, tree-trunks, old wood, etc. ; two species 
are capable of slow movement from place to place. The lophophore 
and tentacular crown of the polypide are horseshoe-shaped. The 
Order owes its name to the presence of a lobe guarding the 
mouth. 
In addition to the sexual, there is an asexual reproduction by 
means of peculiar internal buds termed statoblasts (Fig. 21). When 
the colony dies in the autumn > the liberated buds, securely protected 
in a horny capsule, retain their vitality till the spring ; in due 
season the valves of the statoblast burst open, and the contents 
develope into a new colony. The statoblasts, which resemble small 
seeds, are usually provided with a ring of air cells, which act as a 
float, and in some species spines are present. 
