58 
SHELL GALLERY. 
Case A 1. Section A. Cellularina. — Bugula turbinate, or the Bird's-head 
Coralline (Fig. 6) grows attached to rocks near low water mark in 
the form of spiral tufts about two inches in height, composed of 
narrow flat branches in which the cells are arranged from two to six 
abreast and all facing upwards. Each cell is boat-shaped and with 
Fig. 6. 
A, Bugula turbinate/,, natural size, li, portion x 50. 
a, avicularia ; m, mouth ; o, ovicell. 
[' The Cambridge Natural History.'] 
nearly the whole front surface membranous ; the globular bodies at 
the head of certain cells are the ovicells. Attached to the outer edge 
of each cell is a remarkable object resembling a bird's head, and 
hence termed avicularium, seated on a short stalk. The head and 
beak contain powerful muscles for opening and shutting a horny lid 
