196 
THE OCEAN WORLD. 
at the bottom of the sea, turns itself inwards, forming a sort of purse, 
which seems to imprison the air. From this results a sort of hydro- 
static apparatus, aided by which the animals can float in the water and 
transport themselves from one place to another. The Blue Minyade 
(. Minyas cijanea — Fig. 83) will serve as a type of this family; its 
globose, melon-like form is of azure blue, studded with white wart-like 
excrescences ; it is flattened at its two extremities in its state of con- 
traction, and it has three rows of tentacuia, which are short, cylindrical, 
and white. The internal organs are of a delicate rose colour. Cuvier 
places this species among the Echinodermata, but the observations of 
Lesueur and Quoy, who w T ere acquainted with the living animal, place 
it among the Actiniadse. Many of the species, which are usually 
fixed, are still capable of swimming and of inflating their suctorial 
disks; therefore it is by no means certain that the free habit of Minyas 
cyanea is constant. 
