A guide to the shell and starfish galleries

by British Museum . Department of Zoology; F. J. Bell; R. Kirkpatrick; E. A. Smith

Fig. 13.
Lepralia pallasiana, incrusting a shell. A, natural size; B, cells magnified.

Lepralia foliacea forms a massive coral-like growth composed of thin contorted plates which fuse to form labyrinthine cavities, the plates being constructed of a double layer of cells back to back. A large specimen from the English Channel is exhibited in Case B, upright part. In Lepralia the orifice and lid of the cell have a straight lower margin, but one large group, Myriozoidæ, is characterised by having a notch in the lower margin of the orifice, (Fig. 14, Schizoporella unicornis).

Case B 1.

In many of the Escharina, the front wall of the cell is produced into a stout process or mucro at the lower margin of the orifice (genus Mucronella), or, again, a collar or tube grows up round the primary orifice, thus giving rise to a secondary orifice (Smittia, Porella, etc., Case B 1).

Fig. 14.
Schizoporella unicornis, magnified.

Fig. 15.
Retepora beaniana.

Case B 1.