File:Image from page 167 of "Introduction to zoology; a guide to the study of animals, for the use of secondary schools;" (1900) (14782652034).jpg

Identifier: introductiontozo00dave Title: Introduction to zoology; a guide to the study of animals, for the use of secondary schools; Year: 1900 (1900s) Authors: Davenport, Charles Benedict, 1866-1944 Davenport, Gertrude Anna Crotty, 1866- Subjects: Zoology Publisher: New York, Macmillan company London, Macmillian and co., ltd. Contributing Library: MBLWHOI Library Digitizing Sponsor: MBLWHOI Library

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Text Appearing Before Image: s covering over the back (Fig. 134).These scales are outgrowths of the dorsal part of theparapodia, and serve for respiration. In alliedgenera the scales are covered with bristles,which may be so very long and abundant asto hide the scales. They produce a brilliantiridescence. One of these worms with thegreat bristles may be several inches long andrelatively broad, and is commonly known asthe sea-mouse (Fig. 135). Both Lepido-notus and the sea-mouse occur in out-of-the-way places, - - crevices of rocks at low tide or fairly deepwater, - - so thatthey are not com-monly seen at theseashore. The sedentary Polychaeta aremostly smaller and less familiaranimals than the free-livingPolychseta, but they have aninterest for us in showing howgreatly modified an organismbecomes when it takes on asedentary life. Its swimmingappendages become rudimen-tary ; its eyes are usually lack-ing ; there is no protrusibleproboscis armed with powerfuljaws; the gills become groupedalmost exclusively about the

Text Appearing After Image: FIG. iai.— Lep-idonotus, thescaled worm.Nat. size.Photo, by W.H. C. P. FIG. 135.— Aphrodite, a sea-mouse. r. i.).».— r\imn>uiit5, A, Neil-mouse. i c ±1 i ^ i Nat. size. From Johnston. uPPer end of the bod7> wnere X Eli Kit* AND ITS ALLIES 140 they can be thrust out of the tube ; the mouth comes to lie atthe bottom of a funnel, which receives as food small parti-cles floating in the water; even the segmentation of thebody becomes lost at the hinder end of the animal ; in aword, all those organs which are useful for active carnivo- o rous life have become re-duced to the bare needs ofa quiet herbivorous life.

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