File:Image from page 159 of "Introduction to zoology; a guide to the study of animals, for the use of secondary schools;" (1900) (14598299140).jpg

Clepsine, the flat blood-sucker.

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

View Book Page: Book Viewer About This Book: Catalog Entry View All Images: All Images From Book

Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image: posteriorsetjB. After Greef, from Par-ker and Haswells Text-book. ing a group of annelids of verydifferent appearance. The leeches,or blood-suckers, are flattenedAvorms, Avhich, like the earthworm,show metamerism ; that is, there is a repetition of the in-ternal organs. They are also segmented; that is, thebody has external rings, although they may be obscure.One segment does not, hoAvever, as in the earthworm, 1 0d(TKa;\oj, sac ; <rw/xa, body. 2 ex adder ; ot)/>d, tail. 140 ZOOLOGY correspond with one metamere, but there are three, four,or five segments to a metamere. Leeches have no para-podia and no bristles; but they have a sucking disk atthe posterior end of the body for the purpose of adhesion(Fig. 127). They usually have a smaller, anterior suckingdisk around the mouth, which may or may not be providedAvith teeth, for the purpose of cutting through the skin.When there are no teeth, the pharynx is protrusible,forming a proboscis. With a few exceptions, all leeches

Text Appearing After Image: FIG. 127. — Clepsine, the flat blood-sucker. Ventral view. Posterior sucker atleft. Nat. size. From life. Photo, by E. R. D. live in water ; but in Ceylon there is a land leech whichlives in foliage and attacks man and other animals. (Hlierleeches may live in damp places at a considerable distancefrom water. Leeches suck the blood of fishes and otheraquatic animals. Certain kinds devour worms, insects, andother small creatures. The commonest of the larger blood-suckers of our watersis Nephelis,1 which is not distinctly segmented. It variesfrom black to slate color, and is sometimes striped orspotted. It lives in running water, in ditches, and ponds. 7, wife of Atliamas. THE EARTHWORM AND 7TN ALLIES 141 Clepsine1 is a very flat and broad leech, which iscommon under floating wood. It feeds on snails andcreeps like the inch-worm. The female carries its youngattached to its under surface (Fig. 127).

Note About Images