HYDRO1P-H . TUBULARIIXt. 





and branch until a community of hydroids resembling a 

 tuft of moss has grown up. Fig. 499. From these hy- 

 droids, in turn, bud the free medusae, like Fig. 501. 



TuBULARiD.t. This Family, as 

 restricted by Agassiz, embraces on- 

 ly hydroids whose head is furnished 

 with a wreath of simple coronal ten- 

 tacles, and a proboscis with simple 

 tentacles around the mouth ; and 

 which produce either persistent or 

 free medusae, more or less one-sided, 

 budding from the floor between the 

 coronal tentacles and the proboscis. 

 The Genera Tubularia* Thamnoau- 

 dia, and Paryplia have the medusae 

 persistent ; Hybocodau free, 



The Sub-Order of Sertulariae em- 

 braces those in which the hydra is 

 always pedunculated and attached, 

 and protected by a horny sheath 

 forming a cup around the head ; and 

 the medusae are either free or p. 

 ent. generally flat, but in some 



F c N 



X -- 



bell-shaped, and furnished with numerous tentacles. This 



