CLASS VI. ANNELIDA; ORDER 2. TUBICOLA. 



617 



THE LEODICE ANTENNATA 



TEREBELLA MEDUSA IN ITS CASE. 



OUT OF ITS CASE. 



a smooth covering of hardened mucus ; in others, it is of a leathery or horny consistency ; and 

 in some it is composed, Uke the shells of the mollusca, of calcareous matter secreted by the 

 animal. The annexed engravings show one species, the Terehella Medusa, with incrustations and 

 also without, that is, in its natural state. 



All these worms are unisexual. They deposit their eggs in a mass of mucus, which usually 

 clings to the tube of the parent animal. 



The Serpulce, which form irregularly twisted calcareous tubes, often grow together in large 

 masses, generally attached to shells and similar objects ; while those genera Avhich, like the 

 Terehella, build their residences of sand and stones, appear to prefer a life of single blessedness. 



Vol. IL— V8 



