48 MARINE ANIMALS OF MASSACHUSETTS BAY. 



passed out at the mouth. The tentacles always grow in clus- 

 ters, but are nevertheless arranged according to a regular order. 

 They are club-shaped at their extremities, but are hollow 

 throughout, opening into the chambers of the digestive cavity, 

 two of the clusters thus being connected with each chamber. 

 Their chief office seems to be to catch the food and convey it to 

 the mouth, though they may also be used as a kind of suckers, 

 and the animal not unfrequently attaches itself by means of thes-e 

 appendages. Between every two clusters of tentacles will be ob- 

 served a short, single appendage, of an entirely different appear- 

 ance. These are the so-called auricles, and though so unlike 

 tentacles in the adult animal, when in their earlier stages (Fig. 

 56) they resemble each other closely. But as their development 

 goes on, the tentacles stretch out into longer, 

 more delicate flexible organs, while the auri- 

 cles remain short and compact throughout 

 life. They contain a slight pigment spot 

 representing an eye, though how far it serves 

 the purpose of vision remains doubtful. 

 They are chiefly used by the animal as a 

 means of adhering to any surface upon which 

 it may wish to fasten itself; for the Lucer- 

 naria, though usually found attached to eel-grass in shoal water, 

 has the power of independent motion, and frequently separates 

 from its resting-place, floating about freely in the water for a while, 

 or attaching itself anew by means of the auricles and tentacles 

 upon some other object. The color of this pretty Acaleph varies 

 from a greenish hue to green, with a faint tinge of red, or to a 

 reddish brown. One of its commonest and most exquisite tints is 

 that of a pale aqua-marine. It may be found along our shores 

 wherever the eel-grass grows, and as far out as this plant extends. 

 It thrives admirably in confinement, and for this reason is espe- 

 cially adapted to the aquarium. 



Fig. 56 Young Lucernaria ; magnified 



