First lesson in zoology : adapted for use in schools . Fig. 55)—Echinus nearly righted.—^After Romanes. The Sea-cucumbers.—While the earliest Echinoderms arethe stalked starfish or crinoids (Figs. 45 and 56), the highest 53 FIRST LESSONS IN Z00L0&7. class comprises the sea-cucumbers or Holothurians. In thesea-cucumber, as its name implies, the body is usually long,cylindrical, with a tendency to become worm-like. The skinis not solid, and is muscular. Around the mouth are situ-. Fia. 56.—Pentacrinus. 6, disk with mouth. (Natural size.) ated the ten branching gills, while there are usually suck
First lesson in zoology : adapted for use in schools . Fig. 55)—Echinus nearly righted.—^After Romanes. The Sea-cucumbers.—While the earliest Echinoderms arethe stalked starfish or crinoids (Figs. 45 and 56), the highest 53 FIRST LESSONS IN Z00L0&7. class comprises the sea-cucumbers or Holothurians. In thesea-cucumber, as its name implies, the body is usually long,cylindrical, with a tendency to become worm-like. The skinis not solid, and is muscular. Around the mouth are situ-. Fia. 56.—Pentacrinus. 6, disk with mouth. (Natural size.) ated the ten branching gills, while there are usually suckersarranged in fiVe rows along the body. The trepang or b^che-le-mer {Holothuria edulis) is col-lected in the Moluccas and Australian seas, and when driedis sold for soups in Chinese markets. The infant Holothurian (Pig. 57, A) is a transparent, STARHISH, MA-UnOBlNS, AND SEA-CUOUMBEES. 63 barrel-shaped creature, which usually has ciliated bands orzones around its body; the Holothurian grows up in it, innearly the same way as the starfish grows from tlie larva. On review, we see that the EcMnoderms differ from theworms in the body being very distinctly star-like or radiatedjthat the skin is usually filled with solid, limestone plates,forming a shell; that they all have a tube-like digestivecanal, which lies loose and free in the body-cavity; that inthe sea-urchin there are five teeth for cutting up the food;that EcMnoderms can see and smell, and that most of thempass th
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1894
