72 SHELL GALLERY. 
Case A, Plumatella repens* (Fig. 22) forms brown branching colonies, 
upright wno iiy or partly adherent to the surface of leaves of water plants, old 
wood, etc. The individual cells are club-shaped, and about a quarter 
of an inch long, each cell being attached to the upper back part of 
the cell below ; the statoblasts (Fig 21, B) are simple oval bodies 
with a zone of air cells. 
Plumatella (Alcyonella) fimgosa forms thick masses, composed of 
closely packed vertical tubes. A small specimen * surrounding a 
stick from Hampstead Ponds is exhibited. 
Lophopus crysfallinus* occurs in the form of translucent gelatinous 
blobs, often attached to the slender stems of duck-weed. The 
statoblasts (Fig. 21, C) are elliptical and pointed at each end. The 
polypides are comparatively large, and can be easily observed through 
the transparent surface. When its delicate plumes are fully expanded, 
Lophopus forms a beautiful object. 
Cristatella mucedo* (Fig. 23) occurs in the form of greenish 
translucent oval or worm-like colonies with the polypides on the 
b 
Cristatella mucedo, creeping over a stem of water-weed ; x 6. (After Allman.) 
o, polypides with horseshoe-shaped crown of tentacles ; b, statoblasts seen 
through the tissues ; c, muscular sole by means of which the animal creeps ; 
d, stem of water- weed. 
convex upper surface. The animal slowly creeps about on its 
flattened under surface. 
Freshwater Polyzoa usually prefer dark places, but Cristatella 
creeps along on the stones and pebbles in clear water, and in the 
sunlight. The polypides form three or more concentric rows on the 
upper surface. The statoblasts (Fig. 21, D) are circular, provided 
