ARCHICELOMATA. “77 
Sus-Puy_um III.—Bryozoa.—The Bryozoa are marine 
and freshwater colonial forms. They are all practically seden- 
tary and in many types there is great physiological division 
of labour, some polypes degenerating into mere vibratile 
processes or snapping pincers. 
The class Phylactolemata (with horseshoe-shaped lopho- 
phore) are all freshwater types and the polypes are better 
developed. 
The Gymnolemata (with circular lophophore) are 
nearly all marine and have more modified polypes. 
Their skeletons may be calcareous or chitinous and are, 
as in the case of the hydroid zoophytes, constructed upon 
the same principles of branching as plants. 
Sup-PHyLum IV. —Cuetocnatua.—This is a small 
group for Sagitfa and its allies. Sagétta is practically 
typical of the sub-phylum. It is important, showing the 
possibilities in the Avchicwlomata of an active progressive 
type. 
Sup-PHyLum V.—BracHiopopa.— These are like Wald. 
heimia, all two-shelled, and are divided into the hinged and 
those without hinges. They are like the rest of the Archi- 
celomata of ancient origin and some types, such as Zinguda, 
with a long peduncle used as a motor organ, appear to have 
remained constant in structure from the earliest geological 
times. 
PHYLUM ARCHICCELOMATA. 
1. Ccelomate tridermic metazoa with plano-symmetry. 
2. No metameric segmentation, but a distinct archimeric segmenta- 
tion into three parts. 
3. Coelom well developed and divided more or less into parts 
corresponding: with the segmentation. 
4. Nervous system simple, with dorsal brain, circumcesophageal 
ring and cords, often retaining its connection with the ectoderm. 
5. A simple blood-vascular system of heemoccelic sinuses. 
6. Usually have a free larval pelagic development. 
7. Mostly marine and pelagic, sedentary or burrowing. 
M. ; 13 
