108 COMMON SEAWEEDS. 



in the ^Mediterranean and Atlantic; also dispersed 

 throughout the Pacific and Indian Oceans. 



DICTYOSIPHON PCEXICULACEUS. 



(Name from two Greek words signifying " a net " and ** a tube.") 



Generic character. — Frond thread-like, very much 

 branched ; branches beset with pellucid jointed hairs. 

 The walls of the frond composed of several rows of 

 cells, of which the inner are elongated, the outer 

 small, polygonal, forming a net-like membrane. 



Fructification. — iSaked spores, scattered irregularly 

 over the surface. 



In rock-pools, either on stones or growing parasi- 

 tically on other Algce, this is commonly found. Of a 

 pale olive colour, in tufts from six inches to one or 

 two feet in length. It dries a darker colour, and 

 adheres well to paper. 



Pound everywhere on the British coast and Channel 

 Islands. 



GBACILLAKIA. 



(From gracilis, slender.) 



Generic character. — Prond thread-like, tough, cel- 

 lular. Central cells very large, those of the surface 

 minute. 



Fructification. — Of two kinds or distinct indivi- 

 duals. 1. Tubercles, like little warts, along the 

 branches. 2. Tetraspores imbedded in the surface 

 of the frond. 



