The royal natural history . s, butL. pyramidata occurs on the American coasts, andanother, L. anatina, in the Philippines. The stalkof the former, which is nine times as long as thebody, does not become attached, but moves like aworm, and again, like certain worms, makes tubesout of sand into which it can withdraw. TheLingididce generally live in holes in mud, thebottom of which is lined with sand. The shell-covered body projects above the mud to open andfeed; on being alarmed, it shuts and disappearsbelow the surface. The cilia at the mantle-edgeform a fine sieve which prevents foreign partic
The royal natural history . s, butL. pyramidata occurs on the American coasts, andanother, L. anatina, in the Philippines. The stalkof the former, which is nine times as long as thebody, does not become attached, but moves like aworm, and again, like certain worms, makes tubesout of sand into which it can withdraw. TheLingididce generally live in holes in mud, thebottom of which is lined with sand. The shell-covered body projects above the mud to open andfeed; on being alarmed, it shuts and disappearsbelow the surface. The cilia at the mantle-edgeform a fine sieve which prevents foreign particlesfrom entering the gills. The length of life of ai<i is not more than a year. The sim-plicity of the shell of Lingida, which may best becompared with the cartilaginous structures at theanterior end of a chaetopodous annelid, and its occurrence in the oldest strata inwhich Brachiopods are found, seems to justify the conclusion that it stamls nearestof all the class to the worm-like ancestor. H. and M. Lingula pyramidata (nat. size CHAPTER Worm-Like Animals,—Subkingdom VERMES. Although it is convenient to have a single group in which to include thevarious kinds of worm-like animals, it has been frequently pointed out that thereis no natural sanction for such an arrangement, and that it is highly probable theyought to be divided into several subkingdoms. Accordingly, the present divisionof the animal kingdom must be regarded as a convenient receptacle in which toplace such Invertebrates as cannot be readily assigned to any of the other sub-kingdoms. This being so, it will be evident that it is only possible to describe thisassemblage of heterogeneous elements by stating that the various classes intowhich it is divided resemble each other in the negative feature of not possessingthe characters distinctive of any of the other groups. Bristle-Worms, or Annelids,—Class Annelida. The more highly organised members of this group show unmistakable poi
Size: 1240px × 2016px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectnaturalhistory, booksubjectzoology
