74 ZOOLOGY 
retractor muscles, only two of their mesenteries are continued 
below the level of the oesophagus and bear mesenteric fila- 
Fic. 
Ou 
co @D 
10. 
52.—A longitudinal section through a 
polyp of Pennatula phosphorea. After 
Marshall. 
Mouth. 
Walls of stomodaeum. 
Free edges of mesenteries below the level of 
the stomodaeum, showing short mesen- 
terial filaments. 
Long mesenterial filaments. 
Feathered tentacles. 
Calyx. 
Spicules in body-wall. 
Spermatospheres. 
Mesentery showing protractor and retractor 
muscle fibres. 
Coenenchyme. 
ments, they have a well-developed siphonoglyph, but no repro- 
ductive system. 
The cavities of all the individuals are put into communi- 
cation by means of a number of ramifying coenosarcal tubes 
lined by endoderm. 
The Pennatulidae are phosphorescent, and emit a bright 
glowing light when disturbed, this is said to originate from 
