Elementary Zoology, Second Edition

Part Ii Is Devoted to a Consideration of the Principal Branches of the

animal kingdom; it deals with systematic zoology. In each branch one or more examples are chosen to serve as types. The most important structural features of these examples are studied, by dissection, in the laboratory. The directions for these dissections consist of technical instructions for dissecting, the calling attention to and naming of principal parts, together with questions and demands intended to call for independent work on the part of the student. The directions follow the actual course of the dissection instead of being arranged according to systems of organs, and are intended for the orientation of the student and not to be in themselves expositions of the anatomy of the types. The condensation of these directions is made more feasible by the presence of anatomical plates (drawn directly from dissections). Following the account of the dissection of the type are brief notes on its life-history and habits. Then follows a general account of the branch to which the example dissected belongs and brief accounts of some of the more interesting members of the branch. In these accounts technical directions are given for brief comparative examinations and for the study of the life-history and habits of some of the more accessible of these forms.

It will not be possible, of course, to undertake with any thoroughness the consideration of all of the branches of animals in a single year. But all are treated in the book, so that the choice of those to be studied may rest with the teacher. This choice will of necessity depend largely on the opportunities afforded by the situation of the school, as, for example, whether on the seashore or in the interior near a lake or river, or on the dry plains, and on the relation of the school-terms to the seasons of the year. The branches are arranged in the book so that the simplest animals are first considered, the slightly complex ones next, and lastly the most highly organized forms. But if in order to obtain examples for study it is necessary to take up branches irregularly, that need not prove confusing. The author would suggest that whatever other branches are studied, the insects and birds, which are readily available in all parts of the country, be certainly selected, and with this selection in view has given them special attention. Indeed some teachers may find these two branches to offer quite sufficient work in classificatory and ecological lines.

Part Iii Is Devoted to a Necessarily Brief Consideration of Certain of

the more conspicuous and interesting features of animal ecology. It has in it the suggestion for much interesting field-work. The work of this part should be taken up in connection with that of Part II, as, for example, the consideration of social and communal life in connection with the insects, parasitism in connection with the worms, and also with the insects, distribution in connection with the birds, perhaps, and so on.

In appendices there are added some suggestions for the outfitting of the laboratory, and a list of the equipment each student should have. Here, also, is appended a list of a few good authoritative reference books which should be accessible to students and to which specific references are made in the course of this book. Some practical directions for the collecting and preserving of specimens are also given. (Suggestions for the obtaining of material for the various laboratory exercises outlined in the book are to be found in "technical notes" included in the directions for each exercise.) The author believes that the building up of a single school-collection in which all the pupils have a common interest and to which all contribute is to be encouraged rather than the making of separate collections by the pupils. Waste of life is checked by this, and in time, with the contributions of succeeding classes, a really good and effective collection may be built up. The "collecting interest" can be taken advantage of just as well in connection with a school-collection as with individual collections.

The plates illustrating the dissections have all been drawn originally for the book from actual dissections. Most of the other figures are original, either drawn or photographed directly from nature, or from preserved specimens. Credit is given in each case for figures not original. The drawings for all of the figures of dissections and for all original figures not otherwise accredited were made by Miss Mary H. Wellman, to whom the author expresses his obligations. The thanks of the author are due to Mr. George Otis Mitchell, San Francisco, who kindly made the photo-micrographs of insect structure from the author's slides; to Professor Mark V. Slingerland, Cornell University, for electros of his photographs of insects; to Dr. L. O. Howard, U. S. Entomologist, for electros of figs. 45, 52, 56, 68, 81, 82, 83, 84, 87, 90, and 92; to Professor L. L. Dyche, University of Kansas, for photographs of his mounted groups of mammals; to Mrs. Elizabeth Grinnell, Pasadena, Calif., for photographs of birds; to Mr. J. O. Snyder, Stanford University, for photographs of snakes; to Mr. Frank Chapman, editor of "Bird-lore," for electros of photographs of birds; to Mr. G. O. Shields, editor of "Recreation," for an electro of the photograph of a bird; to the American Society of Civil Engineers for electros of photographs of boring marine worms; to Cassell & Co., for electros of three photographs from nature; to Geo. A. Clark, secretary Fur Seal Commission for photographs of seals; and to the Whitaker and Ray Co., San Francisco, for electros of figs. 46, 59, 60, 61, 64, 65, 93, 94, 97, 98, 99, 100, 102, 119, and 166 to 172, published originally in Jenkins & Kellogg's "Lessons in Nature Study." The origin of each of these pictures is specifically indicated in connection with its use in the book.

The author's sincere thanks are also due to Mrs. David Starr Jordan and to Mr. J. C. Brown, graduate student in zoology in Stanford University, for their assistance in the correction of the MS., and in the preparation of the laboratory exercises respectively. The chapters of Part II relating to the vertebrates were read in MS. by President David Starr Jordan, whose aid and courtesy are gratefully acknowledged. Similar acknowledgments are due Professors Harold Heath and R. E. Snodgrass for reading the proofs of the directions for the laboratory exercises.

VERNON LYMAN KELLOGG.

STANFORD UNIVERSITY, May, 1901.

FOOTNOTES:

This is true if a strictly logical treatment of the subject is held to. As a matter of fact, it is often of advantage to begin with, or at least to take up from the beginning in connection with the indoor work, some field-work, such as the collecting and classifying of insects and the observation of their metamorphosis. As most schools begin work in the fall, advantage must be taken of the favorable opportunities for field-work at the beginning of the year. These opportunities are of course much less favorable in the winter.

The classification of animals used in this book is that adopted in Parker and Haswell's "Text-book of Zoology" (2 vols., 1897, Macmillan Co.). Exception is made in the case of the worms, which are considered as a single branch, Vermes, instead of as several distinct branches.

CONTENTS

PART I. Structure, Functions, and Development of

STRUCTURE, FUNCTIONS, AND DEVELOPMENT OF ANIMALS

I.--THE STUDY OF ANIMALS AND THEIR LIFE.

Our familiar knowledge of animals and their life, 1.--Zoology and its divisions, 2.--A first course in Zoology, 3.

II.--THE GARDEN TOAD (BUFO LENTIGINOSUS).

III.--THE STRUCTURE AND FUNCTIONS OF THE ANIMAL BODY.

Organs and functions, 14.--The animal body a machine, 14.--The essential functions or life-processes, 15.

IV.--THE CRAYFISH (CAMBARUS SP.).

V.--THE MODIFICATION OF ORGANS AND FUNCTIONS.

Difference between crayfish and toad, 26.--Resemblances between crayfish and toad, 27.--Modification of functions and structure to fit the animal to the special conditions of its life, 29.--Vertebrate and invertebrate, 30.

VI.--AMŒBA AND PARAMŒCIUM.

VII.--THE SINGLE-CELLED ANIMAL BODY; PROTOPLASM AND THE CELL.

The single-celled animal body, 36.--The cell, 37.--Protoplasm, 39.

VIII.-CELLULAR STRUCTURE OF THE TOAD (OR FROG).

IX.--THE MANY-CELLED ANIMAL BODY; DIFFERENTIATION OF THE CELL.

The many-celled animal body, 43.--Differentiation of the cell, 43.

X.--HYDRA.

XI.--THE SIMPLEST MANY-CELLED ANIMALS.

Cell-differentiation and body-organization in Hydra, 52.--Degrees in cell-differentiation and body-organization, 54.

XII.--DEVELOPMENT OF THE TOAD.

XIII.--MULTIPLICATION AND DEVELOPMENT.

Multiplication, 57.--Spontaneous generation, 58.--Simplest multiplication and development, 59.--Birth and hatching, 61.--Life-history, 62.

PART II. Systematic Zoology

SYSTEMATIC ZOOLOGY

XIV.--THE CLASSIFICATION OF ANIMALS.

XV.--BRANCH PROTOZOA: THE ONE-CELLED ANIMALS.

EXAMPLE: THE BELL ANIMALCULE (VORTICELLA SP.) [Laboratory exercise], 75.

OTHER PROTOZOA.

Form of body, 78.--Marine Protozoa, 80.

XVI.--BRANCH PORIFERA: THE SPONGES.

EXAMPLE: THE FRESH-WATER SPONGE (SPONGILLA SP.) [Laboratory exercise], 84.

EXAMPLE: A CALCAREOUS OCEAN-SPONGE (GRANTIA SP.) [Laboratory exercise], 85.

EXAMPLE: A COMMERCIAL SPONGE [Laboratory exercise], 86.

OTHER SPONGES.

Form and size, 87.--Skeleton, 88.--Structure of body, 88.--Feeding habits, 88.--Development and life-history, 89.--The sponges of commerce, 90.--Classification, 91.

XVII.--BRANCH CŒLENTERATA: THE POLYPS, SEA-ANEMONES, CORALS, AND JELLYFISHES.

POLYPS, SEA-ANEMONES, CORALS, AND JELLYFISHES.

General form and organization of body, 93.--Structure, 94.--Skeleton, 95.--Development and life-history, 95.--Classification, 96.--The polyps, colonial jellyfishes, etc. (Hydrozoa), 97.--The large jellyfishes, etc. (Scyphozoa), 101.--The sea-anemones and corals (Actinozoa), 102.--The Ctenophora, 107.

XVIII.--BRANCH ECHINODERMATA: THE STARFISHES, SEA-URCHINS, SEA CUCUMBERS, ETC.

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