. Natural history. Zoology. 672 VERMES—CLASS Nearly all the species are marine, and many of them are of considerable size and great beauty. According to structure and mode of life, they are divided into two sub-orders—(1) the Sedeniakia or Tobicola and (2) the Eeeantia. The typical membsrs of the Sedentariahve in tubes of sand, mud, or pieces of shell glued together by the slimy secretion of their skins, or composed of a dense, shelly, chalk-like substance. The worm known as Terebella constructs a dwelling-place of the former kind, gathering together the particles by means of long f
. Natural history. Zoology. 672 VERMES—CLASS Nearly all the species are marine, and many of them are of considerable size and great beauty. According to structure and mode of life, they are divided into two sub-orders—(1) the Sedeniakia or Tobicola and (2) the Eeeantia. The typical membsrs of the Sedentariahve in tubes of sand, mud, or pieces of shell glued together by the slimy secretion of their skins, or composed of a dense, shelly, chalk-like substance. The worm known as Terebella constructs a dwelling-place of the former kind, gathering together the particles by means of long flexible tentacles placed on its head ; while tubes of cement are built by such forms as Serpula and Spirorbis. The latter is the maker of those tubes so much resembling a snail-shell, which are common on our coasts ; while Serpida makes the long, sinuous, serpent-like tubes which may be often found in interlacing clusters encrusting stones and shells of various kinds. When undisturbed these woims may be seen pro- truding from their tubes and waving in the water their gills and tentacles, which are affixed to the head, but upon the slightest alarm they shoot back like a flash out of harm's way, and remain securely concealed within their homes until the danger is overpast. To render it- self still safer within its retreat, the worm called Serpula has one of its tentacles transformed into a veritable stopper, which exactly fits the mouth of the tube and completely closes it up when the worm has withdrawn itself. Although differing from the Serpula and Terebella, and approaching the Errant Polychseta in many characters, the common Sand-worm or Lug-worm {Arenicola marina), so much sought for on our coasts as bait, also belongs to the group of Sadentaria. In this species the gills are repre- sented by plumes situated on the middle segments of the body. At low water on the sandy shores of northern Europe the Lug-worm may be found at times in great quantities, the position of its b
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Keywords: ., bookauthorly, bookcentury1800, bookdecade1890, booksubjectzoology
