86 HISTORY OF BRITISH ZOOPHYTES. 
become more distinct ; several slender arms protrude from the 
orifice of the vesicle, which are seen in vehement action ; and 
after many struggles, an animated being escapes. But this 
has no relation either to the planula of the Sertularia or the 
corpusculum of the Flustra, Alcyonium, or Actinia. It might 
be rather associated with the Medusaria. Before ascertaining 
its origin, I had named it Animalculum tintinnabulum, from 
its general resemblance to a common hand-bell, for the pur- 
pose of recognition. This creature is whitish, tending to 
transparency, about half a line in diameter; the body is like 
a deep watch-glass, surmounted by a crest rising from the 
centre, and fringed by about twenty-three tentacula pendent 
from the lip below. ‘These are of muricate structure, or 
rough, and connected to the lip by a ball twice their own 
diameter. The summit of the crest unfolds occasionally 
into four leaves, and four organs prominent on the con- 
vexity of the body appear at the base. When free, the 
animal swims by jerks or leaps through the water, or drops 
gently downwards; it is incited to move by the light, and 
it has survived at least eight days. Then it disappears ; 
at least, I have not been able to pursue its history longer. 
No other product has ever issued from the vesicles of the 
Sertularia dichotoma,” 
