EXPLANATION (iF PLATK VII. 



Spt)iio'o]ili_vllu]n enornie, Efh. pi. 



Fig-. 1. Lono-itndiiial sectiou of portions of two corallites. — 

 Magnified approximately one-tliiril. 



Fig. 2. Transverse section of portions of three corallites 

 displaying- their functions Avith one another, the 

 central tabulate spaces, and periplieral vesicles. — 

 Magnified ap})roxiinately one-third. 



Fiff. 3. Transverse section of a single coi'allite, with the 

 ... ^ . 



same maa'nitication as that of Fiy. 2. 



