Chap. XI.] 
ACALEPILE. 
399 
undisturbed by a ripple, the minute descriptions are 
rendered perceptible by their beautiful prismatic tint- 
ing. So great is their transparency that they are only 
to be distinguished from the water by the return to the 
eye of the reflected light that glances from their delicate 
and polished surfaces. Less frequently they are traced 
by the faint hues of their tiny peduncles, arms, or ten- 
taculae ; and it has been well observed that they often 
give the seas in which they abound the appearance of 
being crowded with flakes of half-melted snow. The 
larger kinds, when undisturbed in their native haunts, 
PHTSALUS UETICULUS, 
attain to considerable size. A faintly blue medusa, 
