INTRODUCTION. 
and Brywm. One of which Corallines is exhibited at | Bea 
Plate III. and another at B, Plate V. Pats, 
And for want of examining thefe Corallines, as I may fay, a 
alive in their proper Element the Sea-water, others likewife 
had formed erroneous Opinions concerning them, as well as 
myfelf : Some imagining thefe little Veficles only to ferve as __ 
fwimming Bladders, like thofe in the cimaria or Gulph- | | 
weed, and the Quercus Marina or Sea-Oak. 
There are two of thefe Veficles, with the larger Polypes ¥ | 
in them expreffed, magnified near the Middle of the Fig, 4, 
in Plate V. 
Thofe are called Denticles, that look like Teeth, and ae 
placed oppofite to each other on the Sides of the Stem and 
Branch of the fame Figure. Seti 
Thefe larger Polypes are united below by a tender thread- ve 
dy Line, to the flefhy Part that occupies the Middle of the 
whole Coralline. 
~ In fome Inftances, we may obferve, that thefe Animals 
are wrapt quite round in their Veficles, during their Embryo 
State, like thofe in Plate XI. Fig. C. As thefe advance in 
Size, and grow towards Maturity, the Top of the Veficle — 
begins to open, the Animal ftretches itfelf out, and dit 
plays its Arms about in Search of Food; and when it isin — 
the leaft difturbed, it fuddenly contraéts itfelf to the Bottom 
of the Veficle, which clofes after it at the Top. ‘. 
Some Species of Corallines have little elaftic Opercula or — 
Covers to their Veficles, to feeure the Mouth or Entrance — 
of the Veficle upon the Animal’s Retreat to the Bottom of it, i 
asin Plate IIT. Fig. B. : 
Thefe 
