335 



bryozoans attached to the tioatinu' Sarga.ssiim and other 

 alfiw, and the Crustacea, niolluscs and other animals 

 hving among their branches. 



A large number of algfe, especially the shallo^^■-wate]• 

 forms, have attached to them sedentary animals as well as 

 other species of algfP. Among the animals hydroids and bry- 

 ozoans are the most common, though other sedentary ani- 

 mals, such as Spirorbis. are fre(juently very abundant. Ani- 

 mals belonging to the vagrant t^'pe of the benthos are by no 

 means rare. The large fronds of the Laminaria, cast up on 

 our northern shores during every storm, are frequently veri- 

 table menageries of invertel)rate life, — which under favorable 

 conditions may float about for days. These fronds, for ex- 

 ample, are commonly covered with a dense growth of the deli- 

 cate littoral hydroid Obelia geuiculata, while Ibigula and 

 other Bryozoa, and Spirorbis are usually common. The hol- 

 low stem is commonly surrounded by an extensive growth of 

 Membranipora. while not infrequently tubularian and other 

 hydroids find this a suitable resting place. The root-like 

 base of the stem not uncommonly embraces a shell of 

 Modiola or Cyprina, which, in turn, is overgrown with coral- 

 line algae. Sponges are also common among the "'roots'" 

 of the Laminaria. and Acniea. Chiton. Crepidula. Anomia, 

 and other molluscs are attached to the shell, or the stone, 

 which frequently Takes its place. Finally, worms and crusta- 

 ceans are not uncommon inhabitants of the sheltering space 

 between the branches of the "'roots''; and sea-anemones, 

 small star-fish, brittle stars, and sea-urchins also occur, 

 both on the basal portion of the stem and on the frond 

 itself. Such floating menageries may be carried far out to 

 sea, or, what is perhaps more frequent, they are ch'iven on 

 shore. Not infrequently thev are carried far up into estu- 

 aries, and, becoming stranded, are buried in the mud ; or 

 else they are thrown upon niud-tlats. l)ehind some shelter- 

 ing bar or ledge. 



^Yhile these cases illustrate a pseudo-planktonic existence 

 (bie to accident, the cirriped Lepas illustrates an habitually 



