70 



MARINE AOTMALS OP MASSACHUSETTS BAY. 



or clusters at the junction of the radiating tubes with the cir- 

 cular tube, from which they may be seen extending in every 



Fig. 92, 



airection whenever these animals re- 

 main quietly suspended in the water, 

 — a favorite attitude with them, and 

 one which they retain sometimes for 

 days, seeming to make no effort be- 

 yond that of gently playing their ten- 

 tacles to and fro (Fig. 92). These 

 tentacles are capable of immense ex- 

 tension, sometimes to ten or fifteen 

 times the diameter of the bell. The 

 proboscis is not simple as in the Sar- 

 sia, but looks like a yellow urn sus- 

 pended at its four corners from the 

 chymiferous tubes. The oral opening 

 is entirely concealed by clusters of 

 shorter tentacles surrounding the 

 mouth in a close wreath, on which tho 

 eggs are supported. A highly magni- 

 fied branch of the Hydroid stock from 



Fig. 92. BougaiDviUia ; magnified. 



Fig. 93. Ilydrarium of Bougaiuvillia ; magnified. 



