WORMS 319 



There are several varieties of Sea Mats (Flustra), which will be found among 

 the debris on the shore. 



Many other species of Polyzoa will be found attached to seaweeds, matting 

 the surfaces of the larger fronds or encrusting the others. Foliaceous Coralline 

 (Membranipora pilosa) is one such species, looking like narrow strings of velvet. 

 The Creeping Coralline (Scrupocellaria reptans) is another of the 250 species 

 to be found round our coasts. Lepralia is seen as a sort of stony scurf covering 

 seaweeds. Akyonidium gelatinosum is not unlike a stick of barley sugar. 



Annelida. 



To this group belong the Segmented Worms and the Leeches, etc. Almost 

 all the former have minute bristles (seta) concealed in the skin, which act as 

 feet for purposes of locomotion, and for this reason they are known as Bristle 

 Worms. 



The Common Earthworm (Lumbricus communis) is the most familiar, 

 yet few people realize the immense importance of these lowly animals. " It 

 may be doubted," says Darwin, " whether there are many other creatures 

 which have played so important a part hi the history of the world." 



The part they play in opening and renewing the soil can be realized when 

 Darwin's figures are mentioned. He states that there are over 53,000 

 worms in an acre of garden, which pass some ten tons of soil per year through 

 their bodies, and bring up mould from below at the rate of 3 inches in thickness 

 in fifteen years ! 



Points to be noted in examining the Earthworm are the ringed body, 

 with its iridescent skin and curious swollen girdle, and especially the four 

 double rows of minute bristles, eight in each segment, by means of which 

 it moves. It feeds on vegetable matter in the soil. It lays eggs in a 

 cocoon formed by secretions from the skin. This cocoon is gradually stripped 

 off from the body, and, when free, the ends close. 



We have some twenty different species of Earthworms, amongst which 

 the Lob-worm and the Brand-worm are the most brightly coloured, and are very 

 active. 



The Marine Bristle-worms form two divisions : (i) Those which move 

 about freely like the Earthworm ; (2) those which live in a tube or case. 



The Lug-worm (Arenicola piscatorum), which burrows in the sand, lining 

 the walls of its tunnel with a sticky substance, is at first sight a repulsive 

 animal ; but if put into clear water it becomes more attractive, its bristles 

 and the thirteen pairs of red gills lending beauty to its appearance. 



The Sabella (Sabella alveolaria] lives in tubes built up of grains of sand 

 stuck together, and is found in numbers at low-water mark. The Sabellae move 

 up and down these tubes by means of their bristles, and can leave them entirely 

 at will. Placed in an aquarium, they will soon start making new tubes, 

 choosing the grains of sand and placing them in position in a remarkable 



