Handbook of Paleontology 121 



weeds and are often pressed for them. One species (Ser- 

 tularia pumila) is the most abundant of all the hydroids 

 upon the New England coast and is found in profusion 

 in sheltered situations on Fucus and other seaweeds, as 

 well as on rocks. Another species (S. argentea) is com- 

 mon from New York northward. Another hydroid, the 

 Sea Plume (Obelia commissuralis) also is found attached 

 to seaweed. It, too, is plumelike in appearance and has 

 main stems six inches in length. A small iridescent jelly- 

 fish (Lucernaria auricula), about one and a half inches 

 in diameter, may also be found attached to Fucus. It is 

 also found attached to eel-grass, though sometimes free. 

 On seaweeds below half-tide mark are found worms leaf- 

 like in form (polyclads). There are several bryozoans or 

 Moss Animals found on seaweeds. A calcareous form 

 (Crisia) forms bushy tufts one-half inch to one inch 

 high on seaweeds in tide pools, especially red seaweeds. 

 This is a very common form from Long Island Sound 

 northward and also occurs on the Pacific coast. There 

 are other white, calcareous colonies found on seaweeds 

 and also on eel-grass. Still another species forms white, 

 creeping, calcareous stems on seaweed fronds. The Lace 

 Coralline (Membranipora pilosa) is an incrusting variety 

 that sometimes completely covers the fronds of seaweeds 

 and is especially common on Kelp. It is abundant on 

 shores from Long Island to the Arctic and is also found 

 on the northern coasts of Europe. Another species 

 occurs from New Jersey northward. Certain tiny crea- 

 tures known as Sea Spiders (Pycnogonida), because of 

 their resemblance to the spiders, may be found crawling 

 over hydroids and seaweeds. They are purple, gray or 

 brown in color. Another curious little animal, a crusta- 

 cean (Caprella geometrica), is also found in abundance 



