File:Image from page 187 of "Introduction to zoology; a guide to the study of animals, for the use of secondary schools;" (1900) (14598376868).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: rspecies from it. It occurs north toGreenland, and on the northwesternEuropean coast. It has not always FIG. 155. — Littorina ut-occupied our shores, but has been £Tf !he sh£retsnf Nat. size. Photo, by migrating southward. In 1855 Lit- w. H. c. P.torina \vas found in the Gulf ofSt. Lawrence ; in 1869 it was stated to occur in Halifax ;in 1870 a few individuals were found on the Maine coast;during 1871 the species occurred on the New Hampshirecoast; in 1872 one specimen was found at Salem, Massa-chusetts ; in 1875 the first two specimens were taken atWoods Hole, Massachusetts, south of Cape Cod; in 1880the first specimen was taken at New Haven; in 1891 itoccurred as far south as Delaware Bay. Yet at the presenttime it is not very abundant at Cold Spring Harbor, nearthe western end of Long Island Sound. Persons who liveon the coast south of Cape Cod would do well to note care-fully the abundance of the species on their part of the 1 Fig. 155. 2 From littus, the seashore, 168 ZOOLOGY

Text Appearing After Image: tia) heros.nat. size.W. H. C. P. Two-thirdsPhoto, by shore-line. Besides littorea there are two species ofLittorina which were on our coast when records firstbegan to be made. The speciesmay be distinguished by the circum-stances that L. littorea has a blackhead and a heavy shell of brown orolive color. L. rudisl is smaller, hasan angle at the apex of 60° to 70°,and its shell varies in color fromwhite to red. L. palliata2 has an FlG m.- Natica (Luna-apical angle of 95°, and a shellvarying from white to orange, slate,or brown. Natica is another common species with an entire mouth.It can be at once distinguished from Littorina by the umbilicus, or depression situated atthe left of the mouth and in the axis ofthe shell (Fig. 156). In the livinganimal the shell is often quite envel-oped by the large fleshy foot. Themembers of this genus lay their eggsin spiral collars made of aggluti-nated sand. These are common objectsof the seashore. Fulgur3 is a good example of aprosobranch having a

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