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MARINE BIOLOGICAL LABORATORY,
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*** No book or pamphlet is to be removed from the Lab- oratory without the permission of the Trustees.
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INTRODUCTION TO ZOOLOGY
INTRODUCTION TO ZOOLOGY^/
A GUIDE TO THE STUDY OF ANIMALS
FOR THE
USE OF SECONDARY SCHOOLS
BY
CHARLES BENEDICT DAVENPORT, PH.D.
ASSISTANT PROFESSOR OF ZOOLOGY IN THE UNIVERSITY OF CHICAGO
DIRECTOR OF THE BIOLOGICAL LABORATORY OF THE BROOKLYN
INSTITUTE OF ARTS AND SCIENCES, LOCATED AT COLD
SPRING HARBOR, LONG ISLAND
AND
GERTRUDE CROTTY DAVENPORT, B.S.
FORMERLY INSTRUCTOR IN ZOOLOGY AT THE UNIVERSITY OF KANSAS
WITH THREE HUNDRED AND ELEVEN ILLUSTRATIONS
^® ^
— LIBRA ao
gork
THE MACMILLAN COMPANY, -vA
LONDON: MACMILLAN & CO., LTD. 1900
All rights reserved
COPYRIGHT, 1900, BY THE MACMILLAN COMPANY.
Nortoooti
J. S. Cushing & Co. — Berwick & Smith Norwood Mass. U.S.A.
PREFACE
THE general plan of this text-book is at the same time both old and new. Old, because it attempts to restore the old-time instruction in Natural History ; new, because "Natural History" is not to-day what it was a genera- tion ago. The treatment will seem new also in contrast with modern text-books of zoology, since they are devoted primarily to comparative anatomy, a field upon which we lay little stress.
This departure is the outcome of a conviction that the needs of the secondary student are not best met by a course in comparative anatomy. That conviction is not altered by the circumstance that anatomy is fundamental for advanced work in zoology and physiology, for only a sixth of the secondary students go to college, and proba- bly less than four per cent of them continue their zoologi- cal work there. The vast majority of secondary students, then, are not to be zoologists, but rather men of affairs. What the ordinary citizen needs is an acquaintance with the common animals that may be the companions of his country walks, and that may even stray into Wall Street, Dearborn Street, or Commonwealth Avenue. He wants to know where else over the world the common animals of his State are to be found and, as a legislator or as a taxpayer, he wants to know how animals affect man. It is more important for him to know these matters than to know the location of the pedal ganglion of the snail, or
vi PREFACE
to be able to recite the various ingenious hypotheses of the ancestry of echinoderms. Our conviction is, we feel sure, the common conviction of college teachers of zoology, who have often occasion to deplore the ignorance that their students show about common animals. It is the conviction of many other thoughtful men also who have recognized that an interest in nature is a powerful agent in making men more moral, more capable of appre- ciating the world they live in, and of finding satisfaction in living.
The aim of the book is indicated by its title. It is not a treatise on the modern science of zoology. It is a guide to the study of animals, which it is hoped may introduce many students to the sciences of comparative anatomy, comparative embryology, cytology, general physiology, variation and inheritance, and the others that are grouped under "zoology." This book is like a " Synoptic Room ' in the vestibule of a vast museum, containing the most essential things for those who can go in but a little way, but also fundamental for those who can penetrate farther.
The illustrations of this book have received especial at- tention. An attempt has been made to give a lifelike figure of a representative of almost every family mentioned in the text. For courteous permission to reproduce the copied figures we are deeply indebted to many publishers and authors. We have to thank the authorities of the Field Columbian Museum for original photographs, Figs. 301, 302, and 305. Mr. H. W. Menke, of the same institution, kindly gave us permission to use his interesting photo- graphs of live rattlesnakes, Figs. 261, 262. To Mr. V. H. Lowe, Entomologist of the New York State Agricultural Station at Geneva, N.Y., we are indebted for the photo-
PREFACE Vll
graphs marked V. H. L. ; these are published by permis- sion of the Director of the Station. The majority of the original photographs, designated by the initials W.H.C.P., were made by Mr. William H. C. Pynchon, Instructor in Biology at Trinity College, Hartford. All of these, ex- cepting Figs. 183, 184, 188, and 203, are photographs of animals occurring around the Biological Laboratory at Cold Spring Harbor, Long Island. They have thus a cer- tain scientific value as indicating the fauna of that region. As many of these figures are from living animals, probably never before photographed in their natural attitudes, their publication may be considered as something of a contribu- tion to science. Of the other photographs, Figs. 31 a, 122, 276, 281, and 288, marked D. and S., were contributed by Professor N. F. Davis of Bucknell University, Lewisburg, Penn., and Mr. Ernest A. Sterling of the same institu- tion; and Figs. 127, 251, and 259 were contributed by Mr. E. R. Downing, graduate student at the University of Chicago. The figures of birds by Louis Agassiz Fuertes have been reproduced from " Citizen Bird," by Mrs. Wright and Dr. Coues, published by the Macmillan Company. Figures of the types used in the outline of laboratory work have been purposely avoided.
Finally, the authors have to thank several secondary teachers who have kindly made suggestions and helpful criticisms on the outline of laboratory work and the main text. AVe solicit a continuance of these favors to the end that this book may become as perfectly adapted as pos- sible to the needs of secondary instruction in zoology.
C. B. DAVENPORT.
GERTRUDE C. DAVENPORT.
CHICAGO, May 19, 1900.
CONTENTS
CHAPTER I
PAGE
THE GRASSHOPPER AND ITS ALLIES . . 1
Key to the four principal families of Acrididre . . 2
APPENDIX : Key to the principal families of the Orthoptera . 14
CHAPTER II
THE BUTTERFLY AND ITS ALLIES ... 15
APPENDICES : Key to the principal families of Lepidoptera 41
Key to the principal families of Hymenoptera ... 42
CHAPTER III
THE BEETLE AND ITS ALLIES ...... 44
APPENDIX : Key to the principal families of the Coleoptera . 58
CHAPTER IV
THE FLY AND ITS ALLIES ...... 62
APPENDIX : Key to the suborders of Diptera .... 02
CHAPTER V
LlTHOBIUS AND ITS ALLIES .... 74
APPENDIX : Key to the principal families of the Myriapoda . 78
Key to the commoner species of the genus Lithobius . . 79
CHAPTER VI
THE SPIDER AND ITS ALLIES ... 80
APPENDIX : Key to the seven suborders of the Araueina . .95
ix
29390
CONTENTS
CHAPTER VII
PAGE
THE CRAYFISH AND ITS ALLIES 97
APPENDICES : Key to the six chief orders of Malacostraca » 122
Key to the principal families of Podopthalinata . . . 122
CHAPTER VIII
THE DAPHNIA AND ITS ALLIES 125
APPENDICES : Key to the five orders of Entomostraca . . 131
Key to the principal families of Cladocera .... 131
CHAPTER IX
THE EARTHWORM AND ITS ALLIES . 133
APPENDICES : Key to the principal species of Earthworms of the
United States 143
Key to the principal families of aquatic OligocliEeta . . 144
CHAPTER X
NEREIS AND ITS ALLIES 145
APPENDIX : Key to the more important families of Polychseta . 159
CHAPTER XI
THE SLUG AND ITS ALLIES 160
Key to the three orders of Gastropoda 160
Key to the principal families of American Pulmonata . . 161 APPENDIX : Key to the principal families of marine shelled Gastropods of the Atlantic coast of the United States . .174
CHAPTER XII
THE FRESH-WATER CLAM AND ITS ALLIES 178
APPENDIX: Key to the principal families of marine Lamelli- branchiata of the east coast of the United States . . .188
CHAPTER XIII
THE STARFISH AND ITS ALLIES . 192
APPENDIX : Key to the principal classes of Echinodermata . 203
CONTENTS xi
CHAPTER XIV
PAGE
HYDRA AND ITS ALLIES ......... 205
APPENDICES : Key to the principal subdivisions of the Cnidaria 220
Key to the families of the Hydromedusae .... 220
CHAPTER XV
THE PARAMECIUM AND ITS ALLIES 222
APPENDICES : Key to the four classes of Protozoa . . . 229
Key to the subclasses and orders of Infusoria . . . 229
CHAPTER XVI
THE SMELT AND ITS ALLIES ........ 230
APPENDICES : Key to the principal orders of fishes . . . 252
Key to the six suborders of Teleostei 252
CHAPTER XVII
THE NEWT AND ITS ALLIES ........ 254
APPENDICES : Key to the orders of Amphibia .... 266
Key to the families of Urodela 266
CHAPTER XVIII
THE LIZARD AND ITS ALLIES 268
APPENDIX : Key to the four orders of Reptiles .... 280
CHAPTER XIX
THE ENGLISH SPARROW AND ITS ALLIES 281
APPENDICES : Key to the orders of Birds 314
Key to the families of Passeres of northern United States . 315
CHAPTER XX
THE MOUSE AND ITS ALLIES 318
APPENDIX : Key to the orders of Mammalia .... 331
CHAPTER XXI
THE DEVELOPMENT OF THE FROG'S EGG . . . 332
xil CONTENTS
APPENDIX I
PAGE
OUTLINE OF LABORATORY WORK IN ZOOLOGY .... 337
INTRODUCTION .......... 337
EXERCISES 342
I. Grasshopper 342
II. Butterfly . . 343
III. Beetle 344
IV. Housefly or Bluebottle Fly 345
V. Lithobius 347
VI. Spider 348
VII. Crayfish 349
VIII. Daphnia 351
IX. Earthworm . . 352
X. Nereis 353
XI. Slug 354
XII. Fresh-water Clam 356
XIII. Starfish 357
XIV. Hydra 358
XV. Paramecium . . . . . . . . 359
XVI. Smelt 361
XVII. Newt 362
XVIII. Lizard 363
XIX. " English " Sparrow 364
XX. Mouse 365
XXI. Development of the frog's egg 366
METHODS OF EXAMINATION 367
APPENDIX II
A LIST ov BOOKS DEALING CHIEFLY WITH THE ECOLOGICAL AND
SYSTEMATIC ZOOLOGY OF AMERICAN ANIMALS .... 369
APPENDIX III
SYNOPSIS OF THE ANIMAL KINGDOM ...... 383
GLOSSARY . 391
I^NDEX .,»,».••>••> out
INTEODUCTION TO ZOOLOGY
INTRODUCTION TO ZOOLOGY
CHAPTER I
THE GRASSHOPPER AND ITS ALLIES
Relationships. — The grasshopper belongs to an order of insects called Orthoptera.1 In this group of insects2 there is an incomplete metamorphosis during development, so that the general form of the young resembles that of the adult. The anterior and posterior pairs of wings are unequal. The jaws are adapted for biting.
The name " grasshopper ' is applied to two families of insects; namely, the Acridida^8 and the Loeustidse. Both of these families have long hind legs, used in jumping, an elongated body flattened from side to side, and a wedge- shaped head directed downward ; they differ in the length of the antennae.
Habits.- -The Acrididae, or short-horned grasshoppers, are found in both hemispheres. They live, for the most part, on the ground in very diverse conditions, such as in low, damp meadows or in dry uplands, arid deserts, and rocky mountain sides. They are all herbivorous, and may
s, with straight (lying straight out) wings.
2 The principal families of Orthoptera may be distinguished by the key in the Appendix to this Chapter, p. 14.
3 a.Kpi5i.ov, a small grasshopper of Dioscorides.
B 1
2 ZOOLOGY
feed upon almost any green part of plants. Some of tLu species are gregarious (i.e. go in swarms) and may be very destructive.1
Melanoplus 2 is the prevailing genus of North America and covers nearly all of the continent. While in the East certain species of the genus Melanoplus may become destructive to vegetation, the injury done is not so great as was formerly done by the Rocky Mountain locust. At various times for some cause, probably drought, this locust has migrated eastward from its mountain home in countless millions and devastated our Western States as far as the Mississippi River. In 1873 to 1877 the Rocky Mountain locust was so destructive to vegetation in the trans- Mississippi region that Congress appointed a commission to investigate the species. In describing its effect the commission reports : -
" Falling upon a cornfield, the insects convert in a few hours the green and promising acres into a desolate stretch of bare, spindling
1 The following key will aid in determining the four principal Ameri- can subfamilies of the Acrididse : — •
a\. Feet without a claw-pad. Pronotum covering all
the body. Fore wings lobe-like .... Tettigidce
(Tettix Shorthorns)
a*. Feet with a claw-pad ; antennse longer than an- terior femora. 61. Prosternum without a spine.
GI. The plane of the vertex of the head meet- ing the plane of the front of head at an angle, the face looking down . . . Tryxalidce
(Angle-headed Shorthorns)
C2. The planes of the vertex and head round
over into each other .... CEdipodce
62- Prosternum with prominent spine . . . Mehtnoplidce
(Thorn-throated Shorthorns)
s, black ; oir\a, armor.
THE GRASSHOPPER AND ITS ALLIES 3
stalks and stubs. . . . Their flight may be likened to an immense snow-storm, extending from the ground to a height at which our visual organs perceive them only as minute, darting scintillations, , leaving the imagination to picture them indefinite distances bej^ond. ... In alighting, they circle in myriads about you, beating against everything animate or inanimate ; driving into open doors and win- dows; heaping about your feet and around your buildings, their jaws constantly at work, biting and testing all things in seeking what they can devour."
The locusts of the Old World are likewise frequently very destructive. The species that lives in southern Europe, North Africa, Asia Minor, Syria, Java, and Japan is doubtless the locust of the Bible. The description given by the prophet Joel is very vivid and accurate : -
" A day of darkness and of gloominess, a day of clouds and of thick darkness, as the morning spread upon the mountains ; a great people and a strong ; there hath not been ever the like, neither shall be any more after it, even to the years of many generations. A fire devoureth before them, and behind them a flame burneth : the land is as the garden of Eden before them, and behind them a desolate wilder- ness; yea, and nothing shall escape them. The appearance of them is as the appearance of horses ; and as horsemen, so shall they run. Like the noise of chariots on the tops of mountains shall they leap, like the noise of a flame of fire that devoureth the stubble, as a strong people set in battle array. Before their face the people shall be much pained ; all faces shall gather blackness. They shall run like mighty men ; they shall climb the wall like men of war ; and they shall march every one on his ways, and they shall not break their ranks. . . . They shall run to and fro in the city; they shall run upon the wall; they shall climb up upon the houses; they shall enter in at the windows like a thief."
General Development of the Grasshopper. - The common red-legged grasshopper lays its eggs during the fall in holes in the ground which the female drills by means of
4 ZOOLOGY
the horny plates at the tip of the abdomen. The eg thirty to one hundred in number, are laid in a mass and covered with a gelatinous secretion. In these holes, an inch or so below the surface of the ground, the eggs pass the winter and hatch out in early summer into young grasshoppers, looking like adults except for their small size and the absence of wings. As they grow larger they moult several times, i.e. cast off their cuticular coverings. After each moult the body is left soft and colorless, but being freed of its hard, tight casement, it is in a condition to grow rapidly. After each moult also the rudimentary wings (wing-pads) become larger, and the relative sizes of the parts of the body change. Just before the last moult the pupa crawls up some vertical object, clutches it firmly with the hind feet, and remains motionless in this position for several hours. Then the cuticula splits along the middle of the back, the head and body inside the cuticula swell, the head emerges from the case, and gradually the entire body works forward out of the old cuticula ; not easily, indeed, but with violent contortions and pullings. The legs and antennae are especially difficult to free ; they can pass out of the joints of the old skin only because they are soft and flabby ; but as soon as they become exposed to the air their surface secretion hardens into a firm covering. The wings are at first rolled up ; they now expand broadly, dry, and then fold up in the way we see them in the adult.
Allies of the Grasshopper. - The Gryllidae,1 or crickets (Fig. 1), include cosmopolitan insects that have short, cylindrical bodies and live chiefly in hidden places, such as beneath stones or in holes Avhich they make in the
1 Name derived from sound made by crickets.
THE GRASSHOPPER AND ITS ALLIES
ground. Their eggs are laid loosely in these retreats. They feed on plants and, if numerous, may be decidedly injurious to vegetation. They make a familiar chirping noise, the blended sounds of which, as heard on a sum- mer evening, rise and fall in a distinct rhythm. The rate of chirp seems to be entirely determined by temperature, so that one may compute the temperature by means of the formula
^-40
FIG. 1.— Gryllus,
— , , cricket. Nat. size.
Photo, by W. H.
in which T stands for temperature, and
N the number of chirps per minute. The mechanism by
which the chirp is produced is as follows : Near the mid- dle of each of the upper wings of the male cricket is a vein so modi- fied as to form a sort of file, and near the margin of the wing is a thickened scraper. When the up- per wings are brought in contact above the body, and the scraper of one is rubbed across the file of the other, the wings are set in vibration, producing the call.
An aberrant form of Gryllidee is the mole cricket (Fig. 2), whose
FIG. 2.--Grii!iuta?pa bore- f°re feet have become much modi-
alis, mole cricket. Nat. ne(j f()r burrowing, size. Photo, by W. H.
C p 1 he Locustidae,1 or long-horned
1 From the Latin name for the locust and grasshopper, as well as the lobster.
6
ZOOLOGY
grasshoppers and katydids, are close allies of the short- horned grasshoppers already defined. Next to the numer-
FIG. 3. — Orchelimum, meadow grasshopper. Nat. size. Photo.
by W. H. C. P.
ous meadow grasshoppers (Fig. 3) belonging to this group, the katydids are the best known of its representatives. The katydids have their whole body green, like the foliage they
FIG. 4. — Ceuthophilus, cricket-grasshopper. Two-thirds nat. size.
Photo, by W. H. C. P.
inhabit. The wings are large; and when the upper wings are rubbed together, they vibrate, and cause the familiar
THE GRASSHOPPER AND ITS ALLIES 7
note. Other members of this group are the cricket-grass- hoppers (Fig. 4), wingless forms, of a brown color and arched profile, which live under stones and rubbish, and also the cave " crickets," which are colorless and blind.
The Phasmidae^or walking-sticks and leaf-insects, display, to a mar- vellous degree, a protective resem- blance to the twigs and leaves among which they live. The most remark- able forms live in the tropics. They have large wings, which strikingly resemble, in form, color, and vena- tion, either living or dry leaves. Upon those species which resemble dried leaves, blotches looking like fungous patches are found. Even the legs may be thin and expanded, resembling foliage. In our country only the twig-like, wingless forms, or walking-sticks, occur. These in- sects are furthermore protected by changes in color, corresponding with the seasonal color changes in twio-s;
o o
for the young walking-sticks, which
appear in the spring, are green like
the twigs, but in the autumn they
become gray or brown. Figure 5 shows our only common
northern species, Diapheromera femorata. It feeds on
leaves, especially those of the oak, and occasionally does
much damage to trees.
FIG. 5.— Diapheromera, walk- ing-stick of northern U. S. Nat. size. Copied from Packard.
appearance, spectre.
8
ZOOLOGY
The Mantidae l are popularly called praying-mantis, on account of the devotional attitude in which the greatly en- larged front legs are held. Unlike other Orthoptera, they
FIG. (i. — Phasmomantis niroUim. Praying-mantis of southern U. S. Nat.
size. Copied from Packard.
are carnivorous. They hunt and devour other insects some- times larger than themselves, and even prey upon each other. \Yhile most of the species are tropical, one species, Phasmo- mantis Carolina (Fig- 0), is abundant in our Southern States, and another occurs in the Missouri valley.
The Blattidae,2 or cockroaches, are especially creatures of the tropics; and those which live in colder cli- mates frequent warm as well as dark places. The two which are our household pests have been imported from Europe,- -both the small brown " ( 'roton bug," which is found among water-pipes in the kitchen, and the large black species commonest in sugar-refineries, slaughter- houses, and bakeshops. They are omnivorous, eating,
7. - • Wingless cock- roach. Xat.size. Photo, l.v AY. H. C. P.
seer, prophet.
2 blatta, roach of Pliny.
THE GRASSHOPPER AND ITS ALLIES 9
among other things, breadstuffs, clothing, book-bindings, bedbugs, and other insects. We have also a number of native cockroaches, which live chiefly in fields and woods, under stones and logs. Some of these are wingless (Fig. 7).
The following groups are frequently excluded from the Orthoptera, but show a certain relationship with them : -
The Forficulidae,1 or earwigs, are rare in the northern United States, but commoner in the Gulf and Pacific States. In general appearance they resemble rove-beetles, but differ from them in having a pair of forceps at the posterior end of the body. They hide, during the day, in the corollas of
v» * «
* T **f» r
.
/""~ <^n
V
c..
FIG. 8. — Two North American Odonata, belonging to the family Libelhilid: About one-half nat. size. Photo, by V. H. L.
flowers, upon which they feed, and fly about at night. The name earwig seems to have arisen from an unwarranted belief that these insects penetrate into the ears of persons when asleep. They were especially dreaded on account of a fear that thev mio-ht thus penetrate into the brain.
V O A
The Odonata,2 or dragon-flies, have four membranous, net- veined wings, of which the front pair are never larger than the hind ones. Their large heads carry relatively enormous eyes. Two groups of dragon-flies may be distinguished according as the wings, at rest, are extended (Fig. 8) or
1 forfiwila, a small forceps.
" 65ovs, tooth, from the teeth of the mandibles.
10
ZOOLOGY
folded together over the back. Dragon-flies live on the wing, hovering over water and preying upon other insects,
especially mosquitoes. The eggs develop in the water into aquatic larvae which are quite unlike the adult. Especially the jaws are peculiar, being jointed and capa- ble of sudden protrusion, in order to catch the animals which serve as prey. These larvee are easily reared over winter in an aquarium, where not only their ferocious habits, but also their peculiar method of breathing by means of water taken in at the anus, may be observed (Fig. 9).
The Ephemeridae,1 or May-flies. The FIG. 9. - - JEschna, adult May-fly possesses finely veined fore
old larva, or pupa. . 1-1 ^ ^ , i , i
Nat. size. Photo, wings, winch are much larger than the by w. H. C. P. hind wings. The mouth parts are rudi-
mentary and the abdomen terminates in two or three filamentous appendages. As their systematic name implies, they have a very ephemeral existence in the imago state. The imago appears in swarms early in the summer and lives but a fe\v hours, eating nothing and depositing eggs upon or under stagnant water. The larvse feed upon small aquatic plants and insects, breathe by means of gills placed on the back, and live for nearly a year, or even for two or three years, in the immature stages. After many moultings the apparent adult emerges, but, unlike other insects, undergoes an additional moult before laying its eggs. As the insect is subjected to many accidents in its long and defenceless life, each species is preserved only by an enormous fecundity.
. a day, i.e. lasting but a day, short-lived.
THE GRASSHOPPER AND ITS ALLIES 11
White ants, or termites (Fig. 10), while not true ants, live a very similar social or communal life. They differ from ants in the venation of the net-veined wing (when present). White ants are most abundant in the tropics, where they build great conical nests of sand cemented by their saliva ; but they are found also in temperate countries. The common eastern white ant (Termes flavipes) ranges from
FIG. 10.— Termes
Massachusetts southward, and lives in /«?><><?*, white wood or under stones. Three kinds or ' ant-" Nat-
size. Photo, by
castes of white ants occur in any com- w. H. c. P. munity : (1) workers, with small, round heads and concealed mandibles ; (2) soldiers, with large, square heads, and long, powerful mandibles ; and (8) the royal class of kings and queens, which have wings until after the marriage flight. At a certain time in May the males and females from the various colonies fly forth to mate, and thus an interbreeding takes place between colonies. Only a few of the pairs, however, find workers to aid them in establishing a new colony. The queen, after she is established in a new hive, merely produces young, the abdomen becoming immensely swollen and elongated to fifteen centimetres with the eofS's which are
O OO
about to be laid. In tropical countries the termites are troublesome to man by injuring trees and devouring the woodwork of houses.
The order Neuroptera includes certain insects which differ from the Orthoptera in having larvje very unlike the adult, and in having a resting pupal stage in which the metamorphosis into the adult is completed. There are four membranous, clear, net- veined wings, and the mouth
12
ZOOLOGY
parts are used for biting. The largest representative of this group is the Horned Corydalis (Fig. 11), whose larva lives in streams and is called the clobson. The adult is found among fallen leaves or on tree trunks.
The order Hemiptera includes certain insects which resemble the Orthoptera in
FIG. 12. — Hygrotreclms, water-strider. Nat. size. Photo, by W. H. C. P.
undergoing an incomplete metamorphosis; i.e. in having larvie much like the adults in form, and in having no (juiet pupal
stage. They differ from the ( )rthoptera in possessing mouth- parts adapted to
.V
FIG. 13. — Reduvius, the assassin bug. Black. Nat. size. Photo, by W.H. C. P.
FIG. 11. - - Cory- dalis, the dobson. Two -thirds nat. size. Photo, from life by AV.H.C.P.
sucking.
The True Bugs (Heteroptera) in- clude a vast number of generally small insects with very varied habits. Some of them swim through the water and are known as water boat- men ; others skip over the surface of the water and are known as water- striders (Fig. 1-). Others, like the
THE GRASSHOPPER AND ITS ALLIES
Squash Bug, are destructive to plants ; still others, like the Reduviidse, kill injurious insects (Fig. 13).
F'G. 14. — Cicada septonrfccem, the seventeen year locnst.
Photo, by V. H. L.
Reduced.
FIG. 1<>. — Locanium, a scale insect. Remains of females after production FIG. 15. — Pupal case of cicada. Two- of yoiuii>' ; seen as swellings on the thirds nat. size. Photo, by W. H. C. P. bark. Nat. size. Photo, by V.H.L,
14
ZOOLOGY
The Homoptera include insects of very diverse size and form. The largest are the cicadas, or "locusts" (Fig. 14), some of which have the remarkable habit of requiring thirteen or seventeen years for their development. Con- sequently these cicadas appear only at intervals of thirteen or seventeen years. The young bury themselves in the ground and live by sucking juices from the roots of trees. Eventu- ally they come to the surface, leave their lar- val skin (Fig. 15), and FIG. 17. — Schizoneura, a woolly aphis, on flvqwav iq full o-rnwn apple twig. Photo, by V. H. L.
cicadas. In the case of
our common species of cicada there is a brood every year. Besides the cicadas the Homoptera include the little leaf-hoppers and tree-hoppers, the very destructive scale- bugs (Fig. 16), and the mealy-bugs, most of which attack fruit trees and their fruits, and the plant-lice, or aphids (Fig. IT).
APPENDIX TO CHAPTER I
KEY TO THE PRINCIPAL FAMILIES OF THE ORTHOPTEKA
a\. Legs similar, fitted for running .... «2- First pair of legs differentiated for grasping ; pro-
thorax elongated
Blattidce (Cockroaches)
Mantidce (Praying-mantis)
APPENDIX TO CHAPTER I 15
«3. Legs similar, much elongated, and fitted for slow
walking . Phasmidce
(Walking-sticks) «4. Hinder legs stouter or longer than middle pair.
61. Antennae shorter than body .... Acrididce
(Locusts and Short-horned Grasshoppers)
62. Antennae longer than body.
Ci. Tarsi 4-jointed Locustidce
(Katydids and Long-horned Grasshoppers)
c2. Tarsi 3-jointed Gryllidai
(Crickets)
CHAPTER II
THE BUTTERFLY AND ITS ALLIES
Systematic Position. — Butterflies belong to the insect order Lepidoptera,1 characterized by the possession of a long, coiled, sucking proboscis; large, membranous wings, covered with colored scales; and a complete metamorphosis. They occur over the whole globe, but become more numer- ous in species in the tropics of South America and Africa. The number of known species is about twenty-five thousand.2
The Habits and Food of Butterflies. - The idea of a butterfly should not be limited to the winged adult called the imago, for strictly we may call a caterpillar a larval butterfly, and a pupa an adolescent butterfly. Hut in its different stages the habits and food of a butterfly change. Caterpillars feed, for the most part, upon plants. A few - such as the clothes-moth and certain enemies of scale in- sects - -feed upon animal matter. Any single species of caterpillar feeds upon the foliage of a restricted number of kinds of plants. At one extreme we have forms which starve unless they can reach their own particular food plant; at the other extreme there are caterpillars which can live upon the foliage of many kinds of plants, and these are consequently called polyphagous. Certain fami-
1 \e-n-is. scale ; irrepbv, wing.
2 The principal families of Lepidoptera may be distinguished by the key in the Appendix to this Chapter, p. 41.
10
THE BUTTERFLY AN 7) TT8 ALLIED 1<
lies of plants especially serve caterpillars as food. Thus of the hundred species of New England butterflies, eight feed upon oaks, eleven upon willows, thirteen upon the Rosacese, and twenty-eight upon leguminous plants. It follows from the restricted food of many caterpillars, that the range of the species must often be determined by that of its food- plant.
The feeding of the butterfly is mostly done in the larval stage: the pupa can take no food. The imagos of many species touch no food, but in other cases they take small quantities of the nectar of flowers, the sap of plants, and the juice of fruits.
The imagos fly in the daytime, especially in the sun- shine. Certain species are characteristic of the roadside, others of meadows, gardens, or woods, while still others are found flying everywhere. Owing to its ordinarily short life, the imago is usually found not far from the larval food-plant, upon which it lays its eggs.
The Broods of Butterflies and their Polymorphism. — Butterflies winter over in various stages, some in the ego;
O OiT5
stage, some as larvae, others as pup?e or as imagos. Some kinds pass the winter in either of two stages. In whatever stage they tarry, the life current runs very slow, and dur- ing this season few changes take place. In the spring, development goes on rapidly: the winter generation be- comes mature and a summer generation is started. Fre- quently there is more than one brood produced during the summer, even in the Northern States. Farther south two and even three summer broods are still commoner. Where two or three broods occur they may be and usually are quite dissimilar. This is very strikingly illustrated in the case of the Zebra Swallow-tail, Iplii<-li<l<'x c
18 ZOOLOGY
of the southeastern United States, which is multiple- brooded. The early spring form (marcellus form) is the smallest, and has the tail tipped with white; the summer form (ajax) is the largest, and has the tail two-thirds longer than the marcellus form. Other illustrations of this seasonal difference are given by the imported Cabbage Butterfly, the Gray-veined White and the Spring Azure. This dissimilarity between the broods of different seasons is known as seasonal dimorphism or polymorphism. The cause of the difference between the different broods seems to be the dissimilar climatic, especially thermic, condi- tions under which they have developed. Mr. W. II. Edwards in this country, and Weismann and others in Europe, have shown that, when the summer form is kept during development in a refrigerator, the butterfly has the color of the winter form.
Protective Resemblance and Mimicry. — Every one who has visited a natural history museum must have noticed that the polar mammals are apt to be more or less white, while those which live in tropical forests are dark. It is easy to understand that these colors in their proper sur- roundings make the animals which wear them hard to see. This may be of advantage in enabling them to escape the observation of their enemies, which are seeking for them, or to avoid being seen by their prey as they ap- proach. This general resemblance to their background is seen even in some caterpillars, e.g. the tomato-worm, which is colored so exactly like the leaf on which it feeds that it is hard to find. Other caterpillars, belonging to the geo- metrid moths, have the color of the twigs of the plant on which they feed, and the resemblance is heightened by the way they have of stiffening and standing out like a branch
THE BUTTERFLY AND ITS ALLIES
19
from the stem. The moths of the genus Catocala,1 which fly by night, rest by day on the bark of trees, which they so resemble as to be almost indistinguishable. Still more
o
striking is the resemblance which we find between some adult butterflies and dry leaves as seen, for example, in Kal- lima, a butterfly of the East Indies.2 The resemblance of the butterfly to the leaf extends even to details, for the clear patches on the wing resemble holes, while little cir-
FIG. 18. — Catoccdu ilia, the underwing. Upper wings, bark color; lower wings, black with orange bauds. Photo, by C. Billiard.
cular markings resemble the patches made by particular kinds of fungi. This resemblance of an organism to in- animate objects in its environment is known as protective resemblance.
There are certain species of butterflies which appear to be let alone by birds, owing to their disagreeable odor or acrid taste. Examples of such are the Heliconidae, char- acteristic of tropical South America, and the Danaidre, to which family our " Monarch " belongs. Closely resembling
1 Fig. 18. 2 Fig. 19.
20
ZOOLOGY
the Monarch in this country is the "Viceroy," Limenitis arcliippm. This resemblance of the edible Viceroy to the inedible, acrid Monarch, it is believed, is sufficient to
FIG. 19. — A, Kallima, the leaf-butterfly of the East Indies, Hying'; «, at rest. £, Siderone, another leaf-butterfly, flying; b, at rest.
deceive even the birds, and thus the Viceroy gains con- siderable immunity from attack. This resemblance of an edible to an immune species is known as mimicry. The origin of protective resemblance and mimicry are both
THE BUTTERFLY AND ITS ALLIES 21
explained by the theory of Natural Selection or Darwin- ism. Since either of them is of great utility to the organism, their possession, even to a slight degree, how- ever accidentally gained, will give their possessor an ad- vantage over its neighbors in the Struggle for Existence. Consequently it will be more apt to survive and transmit its peculiarity to its offspring. By this means an adapted race will arise and crowd out the unadapted.
Types of the Butterflies. — The group Papilionidse in- cludes the butterflies which fly by day. An account of the most important follows. The Papilios (Swallow-tails) are our largest butterflies. Here belong the yellow Tiger Swallow-tail (turnus), with black stripes, which is found over nearly the whole United States; and the black Swallow- tail (asterias), whose wings are crossed by rows of yellow spots, and whose hind wing bears an orange, black-eyed spot. Its larvae feed on wild or cultivated umbelliferous plants, especially parsnip leaves.
The Cabbage-butterflies (Pieris) have white or yellow- ish wings, tipped and spotted with black, or sometimes with orange. They hover over damp spots in roads or fly through garden patches. The larvae are very destructive and feed on cabbage and other cruciferous plants.
To the Nymphs belong the Angle-wings whose fore wings are notched on their outer edge. Here belongs the butterfly which we sometimes see on warm days in winter or early spring — the Mourning-cloak. This has pur- plish brown wings with a broad yellow border, and a row of pale blue spots. The Graptas belong here, too; they may be told by the silver spot on the hind wing. In the Admirals the wings are less deeply notched. The red Admiral is purplish black above, with an
22 ZOOLOGY
orange band and white spots running obliquely across the upper side of the fore wing. It occurs in England as well as in the United States. Here belongs also the Viceroy, which is not closely related, but is quite similar to the Monarch because the former mimics the latter. They are both of a tawny orange color, with a white- spotted black border on the outer wing margin. The Monarch is the larger, and like the birds has the habit of migrating southward in the fall and returning in the spring. The Fritillaries (Argynnis 1) include some large butterflies, having numerous round and triangular silvery spots on the under side of the hind wing.
To the Lycaenas2 belong the Blues, or Spring Azures, including small satin or steel-blue species which exhibit marked seasonable polymorphism ; the Coppers, orange- red, or brown species; and the Hairstreaks, or Theclas,3 which are small, brown butterflies, usually with two tails to the hind wing.
Types of the Moths. - These include all Lepidoptera, excepting the family of Papilionidse. Seven families are of rather large size (Macrolepidoptera) ; the remaining four are of small size (Microlepidoptera).
The Sphingidae,4 or Hawk-moths, fly swiftly and power- fully, and as they hover over flowers at du,:,k can hardly be distinguished from humming-birds. The larva) have a caudal horn or tubercle. The commonest of these are the tomato or potato " worm," green in color and banded. There are about one hundred species of the Sphingidse in
1 'Apyvwis, the "silvery," a poetic name of Venus.
2 Aikaii/a, a poetic name of Venus.
3 A Greek feminine name.
4 From 20t7£, or sphinx, a fabled monster. The larva of this moth • assumes an attitude like the sphinx.
THE BUTTERFLY AND ITS ALLIES
23
the United States. The Twin-spotted Sphinx (Fig. 20), so- called from the black spots of the hind wing, is destructive
FIG. 20. — Smerinthus f/eminatus, the Twin-spotted Sphinx. Nat. size.
Photo, by W. H. C. P.
to fruit and shade trees. The Pandorus Sphinx (Fig. 21) is of a beautiful olive color ; its larva feeds on vines.
FIG. 21. — Philampelus pandorus, the Pandorus Sphinx. Nat. size. Photo.
hy W. H. C. P.
The Xylotropidae l are chiefly medium to small, clear- winged species which fly at dusk or in daylight. Their
, wood ; r/)e0w, to feed ; because the larvae feed on wood.
24
ZOOLOGY
larvre live in stems of squash, cucumber, etc., and bore
into shrubs and trees (Fig. 22).
The Arctiidae,1 or Tiger-moths, are for the most part con-
spicuously striped or spotted. The larvae are very hairy.
The best known is the furry, brick-red and black Isabella
caterpillar, which can be seen during October in New Eng- land, hurrying nervously in search of winter quarters.
The Bombycidae2 include, as a rule, large and thick- bodied moths. Here belong
o
the silkworm moths - - the only moths of use to man. ( )f these, Bombyx mart 3 is the most generally employed in the manufacture of silk. It originally came from China, feeds on the leaves of the white mulberry, and is reared
Fia.22.-Larvaof oneof theSesiidse Cnie% in China> JaPan> Itilly>
and France. The method of culture is as follows : The eggs ("grains") are laid in the autumn, kept over winter in a dry, airy, and cool place, and hatched when the mul- berry begins to send out its leaves. On these leaves the larvie are put to feed, and after a month they begin to spin. For commercial purposes the larvae are induced
1 From ap/cros, bear.
2 Bombyx-like. Aristotle called the rustling silk /36/x/3os ; hence the name Bombyx for the silkworm.
3 morus, a mulberry tree.
.u in stem. Nat. size. Photo,
THE BUTTERFLY AND ITS ALLIES
to spin the cocoons on prepared twigs or straw. A few days after the cocoon is completed its inhabitant is killed
FIG. 23. — Citheroma rcf/al!x, the Regal moth. Olive and red wings, yellow spots. Nat. size. Photo, hy W. H. C. P.
in-hot water. The cocoon is made of a continuous thread about three thousand metres long, of which, however, only
FIG. 21. — Larva of Citheronia regalis. Head to left. One-half nat. size.
Photo, by W. H. C. P.
about six hundred metres make good silk. This long thread has to be unravelled. The outer end is loosened
26
ZOOLOGY
by soaking the cocoon in hot water ; then several of these ends are brought together and united to form a single fibre
of raw silk. Another imported silk-moth common in parts of the United States is the Cynthia1 moth, whose larva infests Ailan- thus trees. True American forms are the brown Polyphemus 2 moth, whose larva is colored light green, with oblique yellow stripes; the Promethea3 moth, whose cocoon is formed in a folded leaf which is securely fastened by silk threads to its twig ; the
Nat. size. Pho- to, by V. H. L.
FIG. 25. --Adult female of Cll- siocampa clis-
stria. From life. Cecropia moth, expanding six inches, whose coarse tegumen- tary cocoon is bound along its whole length to a twig ; and the nearly equally large Regal moth (^Citheronia regalls, Fig. 23), whose larva is oar largest cater- male of ciisio- pillar (Fig. 24). All of these species are easily reared from the larvae or cocoons.
Closely allied to the Bombycidre are the Tent-caterpillars, which arc never of great size. These are
campa. From life. Nat. size. Photo, by V. H. L.
FIG. 27. — Egg masses of forest Tent-caterpillar, laid on branch. Photo, by
V. H. L.
1 A poetic name of Diana, from the mountain Cynthus.
2 The name of the fabled one-eyed giant blinded by Ulysses.
3 A name hi Greek mythology,
THE BUTTERFLY AND ITS ALLIES
27
destructive species, which infest apple trees and even forest trees (Figs. 25 and 26). Eggs are laid in a ring-like cluster around a twig (Fig. 27). Here they pass the winter and hatch out in the spring as young larva1. The larvae are grc-
FIG. 28. — Nest of Clisiocampa tl/xxtria, the forest Tent-caterpillar, showing the web and the way the larvae crowd together on it. Photo, by V. H. L.
garious and spin a tent-like web, on which they live when not feeding (Fig. 28). When ready to transform, they spin a cocoon made of a yellow powder mixed with silk. The Noctuidae 1 (Owlet moths) are night fliers and are
1 From nox, night.
28
ZOOLOGY
attracted by our lamplights. They are the most numer- ous of all our moths, eighteen hundred species being known from our country. Among the largest members of this
group are the Catocala l moths already referred to. Here also are placed the boll-worm, which eats cotton-pods and green ears of maize ; the cotton-worm, which destroys the foliage of cotton ; the army-worm, which devours grass and young grain ; and the myriad cut- worms, of which some gnaw off young garden shoots at the level of the ground, while other kinds ascend trees and de- stroy buds. To the Noctuidse belong also the Tussock moth (Fig. 29), whose variegated larva bears dense brush-like tufts of whitish hairs on the first four abdominal segments, and is very de- structive to shade trees in our cities ; the Gypsy moth, lately imported into Massa- chusetts, where the state has attempted its annihilation ; and the Brown-tail moth, also lately imported to Boston. FIG. 29. — Notoiophus, The Geomctridae, or measuring-worms,
the Tussock moth. 1-1 ,1 -yr • i
The wingless female are< llke the Noctiuds, very numerous is shown below a and very destructive. They are so
mass of e^ajs she has n i i ' ^i i i
just laid '"""Nat size called because the larvae have a way From life. Photo. of proceeding, as it were, by inches in
their locomotion. One of the most im- portant subdivisions is that of the canker-worms, which often strip fruit and shade trees of their foliage.
1 /card, below ; /caXos, beautiful.
THE BUTTERFLY AND ITS ALLIES
29
The Pyralidae : include among other pests the bee-moth. The larva of this species feeds upon the wax of the hive and constructs silken galleries in the comb.
The Tortricidae 2 contain numerous small, inconspicuous moths, whose larvre are, however, very destructive. The codling-moth is a pest of the fruit-grower, for the larva bores into apples and pears, causing them to fall prema- turely. Many species are called leaf-rollers, from the fact that the larva causes the leaf on which it feeds to curl.
FIG. .'X). — Case-bearing insects on a twig. Phot:), from life by V. H. L.
The Tineidae3 contain the smallest of the Lepidoptera. Their wings frequently bear long fringes. The larvas are so small that they often live in the interior of leaves, and form winding or blotch-like "mines" in them. The larvae of some species make a case out of pieces of leaves united by silk, and carry this about with them. They are known as " Case-bearers " (Fig. 30). Here also belong the clothes-
1 From Trvp, fire ; because the ancients believed these insects to arise from and live in fire.
2 tortor, tortrir, winder, from tonjueo, to roll or wind ; with reference to the habit of twisting up leaves.
3 tinea, moth.
30 ZOOLOGY
moths, of which we have three species. These moths fly early in May, and lay their eggs on woollen cloth, furs, or feathers, upon which the larvse feed.
This review of the Lepidoptera shows us that, on the whole, despite their beauty, they are great enemies of agriculture, since most of them feed on vegetable prod- ucts. Not only do we in this country have an abundance of native forms, but several exotic species have been im- ported; and being thus removed from their natural enemies, their natural fecundity has been unchecked, with the result that they have brought great devastation upon vast agri- cultural districts. The earnest attempts of a state to keep down for a while an introduced pest, even at great expense, is commendable.
The Hymenoptera l include bees, wasps, ants, and certain less well-known insects. They all have four similar mem- braneous wings as the Lepidoptera do ; but unlike the Lepidoptera, their wings are not covered with scales, but are transparent. The mouth parts are formed for biting or for sucking, but the proboscis is not so long that it rolls up as in Lepidoptera.
The Hymenoptera belong to one or the other of two groups, — the stinging Hymenoptera, in which the female is provided with a sting, and the boring Hymenoptera, which are provided with an ovipositor, or long tube, by which eggs can be placed at some distance below the sur- face. To the first division belong the bees, wasps, and hornets, certain digging or boring wasps, and the ants. To the second division belong certain species,- -as, for example, the ichneumon flies,- -which are parasitic on
1 v/j.r)v, skin, membrane ; Trrepov, wing.
THE BUTTERFLY AND ITS ALLIES 31
other insects, the gall-flies, or gall-wasps, and the plant- eating Hymenoptera.1
The bees (Apidae2) include both social species and others which lead solitary lives. Of the latter, some dig their nests in the ground ; others are masons, and build their nests of mud ; others are carpenters, and make tunnels through pithy plants, or even solid wood ; while still others are leaf-cutters. These leaf-cutting bees carve circular disks from rose leaves, out of which they make cells for their young.
Of the social bees, our native species belong to the genus Bombus, — the "bumble' bees. The bumblebees build nests in the ground. The queens only survive the winter. In the spring each queen chooses some mouse nest or other ready-formed cavity in a meadow, and
places within it a ball of
TT , . „ , , FIG. 31. — Bombus, the bumblebee.
pollen. Jpon this iood she Nat. size. Photo, by W.H. c.i'. lays eggs, which develop into
worker bees. As soon as the workers are full grown they begin the task of gathering food, and the queen then de- votes all her energy to egg-laying. Later in the season males and young queens also appear in the nest. The old and young queens dwell together in harmony until autumn, when all the members of the colony perish except- ing the young queens, which pass the winter in some sheltered spot and form new colonies in the spring.
1 A key to the principal families of the Hymenoptera is given in the Appendix to this Chapter, p. 42.
2 From apis, bee.
ZOOLOGY
The introduced, semi-domesticated honey-bees have quite a different social economy. In the first place, the nest is perennial ; consequently the young and old queens cannot remain in the same hive, else the nest would become overcrowded by the presence of too many families. As }roung queens mature, the old queen seeks to destroy
them ; but she is usnsilly forced out of the hive by the workers, a num- ber of which accompany her. This migration is what we call "swarm- ing." 1 When several young queens mature at the same time, duels or repeated swarmings en- sue until only one queen remains. When a new colony is started in a hive or hollow tree, a comb is formed of wax secreted by the worker bees, and into this the queen deposits eggs des- tined to develop into
workers. Still later, eggs destined to form drones are laid in cells larger than those in which workers develop. The de- veloping young workers and drones are fed with honey and bee-bread. Honey is derived from the nectar of flowers, which is lapped up by the workers, is stored for a time in the crop, where it undergoes certain transformations, and is then
FIG. ol«. — Swarm of bees. Photo, by D. and S.
1 Fig. 31 a.
THE BUTTERFLY AND ITS ALLIES 33
regurgitated into the cells. The nature of the transfor- mation of the nectar in the crop of the bee is not precisely known, but it is not great enough to prevent the character- istic flavors of the flowers of the buckwheat, orange, and so on, from being retained in the honey. The bee-bread is made from the pollen of the flowers, which is brought into the hive on the hind legs of the workers. When a new queen is needed for the colony, and the queen cells are empty, one may be produced by the workers in the fol- lowing manner : The partitions between three worker cells are destroyed and two of the embryos are killed. The enlarged cell is rilled with a special nutritive compound manufactured by the workers and known as royal jelly. The remaining embryo, fed upon this especially nutritious jelly, develops, not into a worker, but into a queen.
Of the true wasps ( Vespidie !), some are solitary; others, like certain of the bees, rear their families in the nests of other species (guest-wasps) ; while still others are social. The last group includes our best-known species. The colony of social wasps contains males, females, and workers. As in the case of bumblebees, only the females survive the winter, and in the spring they build small nests and lay
worker eggs. The workers, when grown, FIG. re.— Poiistcs. enlarge the nest and care for the numerous Slightly reduced.
, ,, n Photo, by W. H.
progeny ot the queen. Our social wasps c. P. belong either to the p-enus Polistes,2 which
o o
includes the ordinary black, brown, or yellow bodied
wasps, which build mushroom-shaped nests behind window
blinds and under boards (Fig. 32), or to the genus Vespa,
1 From vespa, wasp. 2 TroXto-r^s, founder of a city.
D
34
ZOOLOGY
Xat. size. H. C. P.
which includes the black and spotted hornets and yellow- jackets, that build great masses of paper combs enclosed
in a nearly spherical gray paper envelope (Fig. 33). These are found attached to trees or parts of buildings. The paper is made of finely masticated wood-fibre cemented b}~ a secretion. Certain yellow-jackets form nests in the ground. The hornets are well
FIG. 33. -Vespa, a hornet, known as among the most vindic- Photo. by w. tive of our northern insects, and their sting is capable of produc- ing considerable pain. In all Hymenoptera the pain of the sting is due to the introduction of a poison into the body of the victim through the stinging organ. This poison is secreted by a special gland of the insect.
The digger and mud wasps (Fossoria1) have the most varied habits. One of the most familiar species is Pclo- poeusf which somewhat resembles a true wasp, but may be easily distinguished from it by the long, slender attachment of the abdomen to the thorax and by the fact that the wings when closed lie flat and horizontal (Fig. 34), while in the true wasps they are folded like a fan. Other species bore into the pith of plants or make burrows in the ground. Many are predaceous, feeding on spiders, cicadas, etc.
The ants (Formicidre 3) constitute a well-known group having features so marked that other insects, excepting
1 From /ossor, digger. 2 TT^AOS, slime. 3 From formica, ant.
FIG. 34. — I wasp, showing po- sition of wings. Xat. size. Photo, by \V. H. C. P.
THE BUTTERFLY AND ITS ALLIES
35
the termites, will hardly be confused with them. From the termites ants may be distinguished by the fact that the first segment of the abdomen forms a small knot or scale lying between the thorax and the remainder of the ab- domen (Fig. 35).
The intelligence of ants is notorious. This intelligence has developed in connection with a highly organized social life. This social life is a communistic one. Homes are built, food is gathered, wars are made, and domains are defended bravely and loyally all for the sake of the entire community. The individual is little regarded, and each
:'~ •• , - - . "
FIG. 35. — Camponotus, the carpenter ant. Uniformly black. Shows scale behind thorax. Nat. size. Photo, by W. H. C. P.
one is born to a caste from which escape is impossible. For, in addition to the distinction of sex characteristic of other species, we have here workers, and these workers may be of different kinds. Thus certain workers get food and care for the young ; others, which serve as soldiers and defend the colony or conduct war, are in some cases pro- vided with powerful jaws. In some species there are three or more classes of workers, each having its characteristic form of body.
Ant Colonies.- -A colony is founded by a female. On warm days the young males and females may leave the nests and take flight in great numbers. This is the mar- riage flight of the queens. Within a few hours after
36 ZOOLOGY
nightfall of the clay of this flight the males perish, while the queens settle down to the ground, tear off their wings, and each of them seeks an appropriate place to begin the formation of a new colony. If by chance a queen is dis- covered by some of her workers, she is cared for by them ; otherwise she must get on alone. She makes a small nest and lays eggs, which quickly develop into workers, which then assume the task of constructing the nest of the new colony. The nests of our ordinary species consist simply of tunnel-like passageways dug in the ground and enlarged at intervals to form small chambers. Most species dig their nests preferably under protecting stones or the roots of trees ; in other cases a hillock of earth and twigs, an "ant-hill," is constructed. These mounds may attain a diameter of from six to ten feet.
Ant Language. — In connection with their communal life ants have gained a power of communication. By the agency of their antennse, with which two comrades are constantly stroking each other, they can tell each other of the whereabouts of food, of the approach of an invading army, or of the need of aid. They distinguish members of their own community from those of other communities, and recognize one of their number, even after a long ab- sence, and receive it back to the colony with demonstrations as of joy.
Social Life of Ants. — To illustrate the complex social life of ants, a more detailed account is here given of certain interesting .species. Certain ants, such for instance as our Formica1 difficilis? a rust-red species often found living beneath large, flat stones, make slaves of another species of ant which (a curious coincidence) is a dark-colored species. In at least one slave-making species the jaws have become
i Ant. 2 Difficult.
THE BUTTERFLY AND ITS ALLIES
37
so modified to aid it in capturing slaves that it is absolutely dependent upon its slaves for food, and it would die surrounded by food were none of its slaves at hand to feed it.
The Agricultural Ant. — One of our most interesting ants is the Agricultural Ant of Texas (^fyrmical molefaciens2). This ant makes a circular clearing about its mound, upon which it allows only one species of grass to grow. Indeed, some observers maintain that the seed of this grass is planted upon the clearing by the ants. Certain it is that the ripe seeds of the grass are carefully harvested by the ants and stored within the chambers of their mound. From time to time the seeds are brought out and dried to prevent sprouting. During rainy sea- sons, when the seeds germinate despite all pre- cautions, the ants are said to nip off the sprout upon its first appearance.
The army ants, of which there are several species, occur in great numbers in tropical South America. Like many other species which live by hunting, they migrate from a locality after having exhausted it of their food. While on the march, the young of the species are trans- ported by some of the adults. When an army of these ants approaches a place, every living animal endeavors to escape. The breeding birds
must be on the alert to pick off the advance Fie. 3G.-Ptmpfapeda-
1 . hs, a parasite on the
guard to prevent them from returning to the
army with news of the presence of nestlings. Insects of all sorts, young and old, fall a ready prey to these swarms. Some spiders escape by suspending themselves by their threads, and insects which resemble leaves often find safety in keeping rigidly still. When an army of these ants enters a house, the inhabitants find it wisest to leave the invaders in possession, for in a few hours the house is cleared of every living thing — moths, cockroaches, rats, mice, all have fled or been devoured.
The leaf-cutting ants are another tropical American species. The
caterpillar of Clisio- campa. Upper figure female, lower male. Photo, by V. H. L.
, ant.
2 Mole or mound builder.
38
ZOOLOGY
colony is very perfectly organized. The duties of the workers are divided among different gangs. Thus, when a tree has been selected, one gang ascends the trunk and cuts the leaves in pieces of a definite shape. The pieces flutter to the ground, are picked up by another gang and carried to the entrance of the ant-hill, where they are de- posited to be carried into the nest by a third relay. The bits of leaves are used to line certain of the passageways, and a fungus is grown upon them which serves the ants as food. The leaves are probably stored to provide this fungus food.
The parasitic Hymenoptera have the habit either of lay- ing eggs in the body of another insect, — one of the plant- lice, a caterpillar, or other species, — or else they lay their eggs in the nest of some species of insect so that the larva can make its own way into the host (Figs. 36-38). The long, tail-like ovipositors of the female ichneumon are, in
some cases, used to drill holes into trees occupied by insect burrows so that her eggs can be laid therein. These parasitic species are invaluable to agriculture in keeping down injurious insects.
The gall-wasps, popu- larly not distinguished from the strict gall-flies, are familiar to us from thei;1 works. They lay eggs in various kinds of plants, especially in oaks and members of the rose family. An excessive growth of the plant tissue, called a gall, is caused either by a poison dropped into the plant with the
FK;. -37. — Cocoons of Microgaster, a para- sitic hymenopter, on a sphinx larva. Photo, from the living object by V. H. L.
THE BUTTERFLY AND ITS ALLIES
39
egg, or by the irritation of the developing embryo.1 The galls of gall-wasps are often more or less spherical masses
FIG. 38. — Ophion, an Ichneumon which infests caterpillars. Nat. size. Photo.
by W. H. C. P.
which are closed, in consequence of which the confined insect must bore its way out. The galls made by the same
FIG. ol). — Larvae of saw-tiy on grape leaf. Photo, by V. H. L.
1 Cf. Fig. 69, p. 07.
40
ZOOLOGY
species of insect on one kind of tree are quite similar, but if the same insect stings another species of tree, a different kind of gall is produced. Also when different species of gall-wasps sting one and the same leaf, the galls will be unlike. Hence the characteristic form of the gall is determined both by the species of plant and by the
species of insect which lives in it. It is interest- ing to collect galls, watch for the emerging Avasps, determine their species, and thus get their entire life history. The gall- wasps are, on the whole, injurious to agriculture.
The plant-eating Hy- menoptera are extremely destructive pests. The young are known as "slugs," from their re- semblance to the true slugs, which are snail-like animals. They infest pear trees and rose bushes, leaving scorched, dried leaves behind them.1 Here also belong the currant-worm and the saw- flies (Figs. 39 and 40;, which eat leaves like caterpillars, but differ from them in having twelve or sixteen prolegs instead of ten.
FIG. 40. — Eggs of Nematus, a saw-fly on gooseberry leaf. Photo, by V. H. L.
1 See "The Pear Slug," in Circular No. 26, 2d Series, U. S. Depart- ment of Agriculture, Division of Entomology.
APPENDIX TO CHAPTER II
41
APPENDIX TO CHAPTER II
KEY TO THE PRINCIPAL FAMILIES OF LEPIDOPTERA
ai. Antennae club-shaped at apex ; wings when at rest held vertical (Fig. ID)
«.2. Antennae usually having the form of a bristle, spin- dle, or thread, often with a comb ; wings at rest held out flat (Fig. 23), or else folded over body like a gable roof (Fig. 25). l>i. Hind wing usually with one or two dorsal veins
[Macrolepidoptera, large-winged moths]. Ci. Antennae spindle-shaped or keeled, rarely club-shaped ; wings small ; dusk fliers. d\. Antennae prismatic ....
do. Antennae not prismatic, but
e\. attenuated at end, occasionally pectinate ....
/!. Clear winged (Sesiina). f.2. Wings speckled, antennae much longer than head (Cossina). /3. Antennae hardly longer than
head (Hepialina).
BO. club-shaped, occasionally pec- tinate ...
C2. Antennae bristle- or thread-like ; wings
mostly broad, night fliers. d\. Wings when at rest placed like a gable roof over body, or envelop- ing it ; proboscis well developed. e\. Subcosta of hind wing united with radius for a considerable dis- tance ; body hairy .
e». Subcosta of hind wing nearly or quite distinct from radius ; ab- domen ending conical ly .
PapilionidcB
(Butterflies)
Sphingidce
(IIa\vk-inoths)
Xylotropidaz
(Wood-borers)
Zygamidm
(Zygenids)
(Tiger-moths)
Noctuidce (Owlet-moths)
42 ZOOLOGY
d%. Wings as in d\ ; proboscis usually weak ; abdomen rounded at apex ; antennae pectinate . . . Bombycidce
(Silk-worms)
ds. Wings rest horizontally ; proboscis
weak Geometridce
(Measuring-worms)
61. Hind wing with three dorsal veins [Microlepi-
doptera, small-winged moths]. Ci. Wings not divided or parted.
d\. Wings rest in gable fashion, with
short fringe or none at all. e\. Anterior wings elongate-tri- angular ; palps extending be- yond head .... Pyralidce
(Pyralids)
62. Anterior wings much elongated, cambered ; antennae with thick basal segment ; palps slightly protruding .... TortricidjR
(Leaf-rollers)
di. Wings at rest, flat or enveloping the body ; the anterior wings with long fringe ; strongly developed palps Tineidce
(Leaf-miners)
c2. Wings divided or parted .... Pterophoridce
(Plume-moths)
KEY TO THE PRINCIPAL FAMILIES OF HYMEXOPTERA
a\. Trochanter simple ; female with sting.
61. First segment of the hind leg more or less compressed, at least on inner side, and
often thickly hirsute Apidce
(Bees)
62- First segment of hind leg more or less cylin- drical, neither markedly broadened nor hairy.
APPENDIX TO CHAPTER II 43
* *
Ci. Anterior wings folded once lengthwise ; antennce usually clearly bent at an angle Vespidw
(Wasps)
c2. Anterior wings not folded lengthwise. di. Abdomen appended or peduncu- late, oval or broadest anteriorly, gradually tapering posteriorly .
Superfamily Fossoria
(Digger and. Mud Wasps) d2- Abdominal stalk formed of one or two knots or scale-like rings ; an- tennae flagellum-like . . . Formic-idai
(Ants)
«2. Trochanter of two segments ; female with ovi- positor.
61. Abdomen not sessile, but appended or pedun- culate ; anterior rings without lancet-cells; hind wings with two root-cells .
Superfamily Entomophaga
(Parasitic and Gall-producing Ilymenoptera)
62= Abdomen sessile (or continuous with thorax) ; anterior wing with lancet-cell ; hinder wing with three root-cells . . Superfamily Phytophaga
^Plant-eating Hymenoptera)
CHAPTER III
THE BEETLE AND ITS ALLIES
BEETLES (Coleoptera1) can be distinguished from otliei insects by the fact that the anterior pair of wings (elytra) are modified to form two horny shields, covering the pos- terior part of the body, while the posterior pair of wings are membranous. The mouth parts are formed for biting.2
During development, the beetles, like the Lepidoptera and Hymenoptera, undergo great changes of form. These changes may be observed in the potato-beetle. In this species the orange-colored eggs are deposited often in a very regular manner on the under side of the potato leaf. Here they develop for several days. In about a week, however, the young, reddish, black-spotted larva, or "grub," emerges. Like the adult beetle, it has three pairs of tho- racic legs. After feeding actively for two or three weeks, the larva descends into the ground, forms a naked yellow
FIG. 41. — Larva of Lachnosterna, the June bug, at roots of aster. Photo, of
living animals, uat. size, by V. H. L.
s, sheath ; 7rrep6v, wing. 2 A key to some of the chief families of Coleoptera is given in the
Appendix to this Chapter, page 58.
44
THE BEETLE AND ITS ALLIES
45
pupa, and emerges in about ten days as an imago. From two to four broods are produced during the year. The adult beetles hibernate in the ground, emerging and laying eggs the following spring.
The larval habits of the different kinds of beetles are extremely varied, quite as varied as the habits of the adult. The details of these differences may be best considered when we take up the different kinds of beetles.
The number of species of beetles which have been de- scribed is very great, probably over one hundred thousand. Of these, over ten thousand inhabit America, north of Mexico. Fortunately this vast number can be included within a relatively small number of families. Leaving the precise definition of these families to the table in the Appendix, we mav here consider
•/
certain of the salient general characteristics.
The running beetles include two principal families. The first of these is the tiger-beetles (Cicindelidse :), which
are colored bright brown or green. They frequent sunny places, especially paths or sandy shores, and are extremely agile.2 The larva' are hunch-backed creatures, have a huge head armed with long jaws, and live in burrows, at the entrances to which they lie in wait for their prey.
The second family of the running beetles includes the ground-beetles (Carabidae3 in narrow sense). This family
1 Derived from candda, caudle. 2 Fig. 42. 3 Kapafios, beetle.
FIG. 42. — Three common species of Cicin- dela, the tiger-beetle. Left, red-copper bronze; middle, brown, with yellow mark- ings; right, bright green, cream-colored markings. From Packard.
46
ZOOLOGY
is composed of about ten thousand species, of extremely varied form, size, and coloration. Most of them are of a shiny black color, usually with longitudinal ridges or rows of piinctations on the elytra.1 They live on the ground, and during the daytime they are concealed underneath boards and stones, but at night they fly and climb trees and shrubs in search of other insects. They are most abundant near watercourses, and are sometimes found on the seashore. Some species emit ill-smelling fluids, often
with a popping sound. These fluids serve to defend them from their enemies. Some species are vegetable feeders, for instance one species whose larv?e are destructive in the South to young Indian corn.
The next two families, Dytis- cidae2 and Gyrinidae,3 include beetles which are quite as de- structive to animal life of the water as the runners are to those of the land. The Dytiscidse are often large species, which have long, thread-like antenme. The Gyrinidce have short antennse and whirl around on the surface of the water, often in groups. Each eye is divided into an upper half, used for looking into the air, and a lower half, used for looking into the water. The larvre of both of these families have a long and spindle- shaped or flattened body and live in the water.
1 Fig. 43.
2 dvT-r)s, diver ; Sun/cos, fitted for diving.
3 From 70/30S, circle ; because this beetle swims in a circle.
FIG. 4-'i. — Calosoma scrutator, the searcher, a ground-beetle. Nat. size. Photo, by AV.H.C.P.
THE BEETLE AND ITS ALLIES
47
Another family of aquatic beetles includes Hydrophilus l and its allies, which are less strictly carnivorous than the last two families. Their antennae are short and club-shaped, and their bodies are plumper than that of Dytiscus, which is of about the same size and lives in similar places.
The next family includes certain short-winged beetles (Staphylinidte 2), so called because the elytra cover only a small part of the abdomen (Fig. 44). These beetles (" rove -beetles") are usu- ally black and of small size. They are very common under decaying or- ganic matter, stones, and other objects lying on the ground. They run swiftly. Some species mimic ants and wasps. Not only do they resemble these
FIG. 44. — A gus, a staphylinid. From Packard.
FIG. 45. — A staphylinid elevating the abdomen. Photo, by W. H. C. P.
Hymenoptera in the general form of the body, but also in the movements of the tip of the abdomen, which, when the
1 i>5ajp, water ; 0/Xos, loving.
2 (rTa^i/AZVos, from crra^iyXiy, a cluster, is Aristotle's name for a certain insect.
48
ZOOLOGY
animal is irritated, is raised as though to sting (Fig. 45).
These beetles feed upon decaying animal and plant matter;
consequently they are useful scavengers. Some species in- habit the nests of ants and of termites, but their relations with their hosts are unknown. The larvae are not unlike the adults, and inhabit similar situations.
The carrion or sexton beetles (Silphi- dre l) are usually of medium or large size, and are either stout-bodied, with red spots on each elytron (Necro-
phorus2), or very much flattened and FIG. 46. — Silpha amer- .,,,-,/ -, -, ^ ^.,, ,,. ...
icana, a carrion bee- with thin-edged elytra (Silpha, -b ig. 46).
tie. From "Standard rpjie Species of NecropllOrilS are power- Natural History." *
ful animals. When one or more pairs of these beetles discover a dead bird or small mammal on the ground, they dig out the earth from underneath and pile it upon the animal until eventually the car- cass is entirely buried. Then the female deposits her eggs upon the body, so that a rich supply of food is provided for the young larvre which hatch from the e^o-g. The members
r IG. 4(. — Antnrenus, the niuse- of the geilUS Silpha do not bury um pest, a dermestid. Left,
a carcass, but live and rear their la!'^: "lkldl£ f1^' ri-ht'
adult. From Packard.
young beneath it.
While the families of beetles hitherto considered are in general useful to man by acting as scavengers or by destroying insects injurious to vegetation, we have now
1 <ri'X0i7, an ill-smelling insect.
2 i>eKp6s, a dead body ; <£f/ocj, to bear.
THE BEETLE ANT) ITS ALLIES
49
name from the resemblance of their long, often
to consider a family, that of the Dermestidae,1 which is economically directly injurious in a variety of ways. The species of this family include small, oval, or elongated beetles with gray or brown markings, which are due to scales and can be rubbed off. The larvae are fuzzy, and are more injurious than the imagos. They feed on wool, leather, fur of all sorts, as well as on dried and salted meats. Our most destructive species have been imported from Europe. One of them is the carpet-beetle or "buf- falo-bug," which lives upon carpets and clothing. The museum pest is a closely related species which works sad havoc with insect collections, unless these are subjected several times a year to the poisonous fumes of carbon disulphide (Fig. 47).
The stag beetles (Lucanidee 2) have received their com- mon
branched mandibles to the antlers of a stag. The plates of the club-shaped antenna cannot be brought compactly together, as in the next family. The adult beetles live on the sap of trees, and the larvre bore into the wood of the roots and trunk. The common large stag-beetle, which is often attracted into our houses by lamplight, is Lucanus dama. In the South the giant stag-beetle {Lucanus elepJians) is found, with mandibles which, in the case of the male, are more than three-fourths the length of the body.
Closely allied to the last is the great family of lamelli- corn3 beetles, in which the ends of the antennae bear flat,
1 Sep/j.r)<rrr)s (5fy/ia, skin; e<r0t'u>, to gnaw), a worm which destroys pelts.
2 From lucus, grove. 3 lamella, a small plate or leaf ; cornu, horn.
E
FIG. 48.— Dorcus,
a stag - beetle. Nat. size. Photo. by W. H. C. P.
50
ZOOLOGY
•
closely applied plates. This family includes many very
large insects. We can separate it into two groups, - - the
scavengers and the leaf-chafers.
The scavenger lamellicorns, commonly known as tumble- bugs, live in the dung of horses and cows, which they form
into balls and roll long distances (Fig. 49). The dung-rolling habit has long excited interest ; indeed, among the Egyptians it was a source of superstition. So high was the veneration of this people for this their sacred beetle, that they reproduced it in their paint- ings and sculpture. The ball of dung is really intended for the dep- osition of an egg, and it is rolled by both males and females to a hole
in the ground which has been dug in a safe place for its
reception.
The leaf-eating lamellicorns include the May-beetles or
"June-bugs' (Lachnosterna1) which are attracted by
lamplight at night. They enter with a
busy humming sound, soon come in violent
contact with the wall or a piece of furni- ture, and fall heavily to the floor. They
feed at night upon the foliage of trees and
shrubs. Another common species is the
rose-bug,2 which bears the name Macro-
dactylus 3 subspinosus. It is destructive to
the blossoms and young fruit of grapes,
FIG. 49. — Copris, a tumble- bug. Nat. size. Photo, by W.^H. C.P.
n sheep's wool ; arepvov, the chest. 2 Fig. 50. 3 /^a/epos, large ;
finger.
FIG. 50. — Macro- dactylus, the rose-bug. Nat. size. Photo, by W. H. C. P.
THE BEETLE AND ITS ALLIES
51
FIG. 51. —
rujlpes, a metallic wood-borer. From "Standard Natural History."
roses, and other members of the plant family Rosaceae.
The larvae of the May-beetles are the fat, whitish, bowed
grubs which are often found in the spring in the soil where
they have passed the winter. They are
very destructive, for they feed on roots of
grass, herbs, and shrubs (Fig. 41).
Another family of beetles very destruc- tive to trees is that of the metallic wood- borers or Buprestidae.1 The adults are
found upon flowers and the bark of trees,
where their metallic colors glitter in the
sunshine (Fig. 51). The larvae, which
have relatively enormous heads, bore
beneath the bark of trees or into the
wood. This family reaches its highest
development in the tropics.
Closely allied to the foregoing is the family of click
beetles or Elateridae.2 These have the power, when placed
on their backs, of leaping into the air by means of a special device on the under side of the animal (Fig. 52). The larvae, called "wire-worms' because of their round, hard bodies, live under the bark of trees and in rotten wood or upon vegeta- tion in the ground. They are most de- structive to germinating grain, especially maize. It requires several years for them to mature.
The fireflies (Lampyridae3) make up
?, among the ancients a poisonous beetle, living in grass by swallowing which oxen (/SoOs) swell out (trp^d^ .
2 eXariyp, driver. 3 Xd^Trw, to shine ; oupd, tail.
FIG. 52.— One of the click beetles. Nat. size. Photo, by W. H. C. P.
52
ZOOLOGY
a
another and a well-known family. They are distinguished by soft wing-like elytra and by the great expanse of the
thoracic shield, which partly or wholly covers the head. Certain non- luminous species live on flowers, especially the golden-rod ; the lumi- nous species are noctur- nal. The light-giving or- gan lies in the abdomen. The larv?e also are lumi- nous and are known as glow-worms (Fig. 53). A family of consider-
FIG. 53. -- Photuris, a firefly. «, larva; - .
b, adult. The lines to the left of figures able economic import- represent actual lengths of animals. From £ince js that of the TenC- Packard. .
briomdae, so called from the principal genus Tenebrio,1 the larva of which, known as the meal- worm, occurs in flour and cereals and looks much like a wire-worm.2 The adult beetle is black and about one-half an inch long (Fig. 54). The family is not abundant in the northeastern part of the United States.
0 i i • i f i i^ i ,1 FiG.54. — Tenehrio, the meal- Several kinds Ot adult beetles worm Left, larva; right,
can be found under the bark of adult. From Leunis.
1 Miller, because it lives in flour.
2 These larvse are reared by bird-fanciers for bird food, and may be obtained in bird stores.
THE BEETLE AND ITS ALLIES
53
trees, but these are mostly carnivorous and are seeking their prey there. The minute bark-borers or engraver beetles (Scolytidie1), however, feed on the innermost layer of bark. As they eat in lines, a pattern is formed which is characteristic for each species. Along these lines, niches are made in which eggs are laid and larva? hatch. The borings are injurious to the trees, often causing their death. Herbaceous plants also are infested by certain spe- cies. An example is the destructive Pine Borer (Fig. 55), which is common throughout the United
States and Canada.
One of the most injurious
of all the families of beetles
is that of the weevils (Cur-
culionidse2). These beetles
are small, and their heads
are drawn out into a long
snout by which they bore
holes in plant tissue to
receive their eggs (Fig.
56). The dull colors of
the beetles render them in- conspicuous to insect-feeding birds. The number of species is reckoned at over ten thousand, and the family is of world- wide distribution, its dispersion having been aided by com- merce. Grain-weevils are great pests in stored wheat, rice, or maize. They also oviposit in the planted seeds. Buds are attacked, and nuts, stone fruit, and fleshy fruits are made " wormy ' by them.
Extremely destructive also is the great family of long-
FIG. 55. - - Den- droctonus, an engraver bee- tle. Magnified 2. 5 times. From " Standard Nat- ural History."
FIG. 56. - - Balani- nus, a weevil, of brown color. From Packard.
1 From o-KoXuTTTw, to mutilate.
2 curculio, a grain-weevil.
ZOOLOGY
horned beetles, "buck-beetles," (or Cerambycidse1), of which about six hundred species are known in North
America alone. The an- tennae and legs of these beetles are very long.2 The larvae bore into even the hardest woods, and live in the wood for two or three years. Timber and shade trees are thus greatly dam- aged. A favorite collect- ing ground for Ceramby- cidre is the golden -rod, where the black, yellow- banded locust borer, Cyllene robince (Fig. 59), is pretty sure to be found. Still another destructive family is that of the leaf-eating beetles, — the Chrysomelidre,3 to which the potato-beetle belongs. These beetles are thick and round in shape. They lay their eggs upon the leaves of plants. The larv?e feed on the leaves or burrow in the stem. Usually the larva is conspicu- ously colored and exposed, and relies for protection upon its dis- agreeable odor and taste. The most destructive species to agri- culture in the northern United
FIG. bl. — Prlonus laticollis, a long- horn. Black. Nat. size. Photo, by W.H.C.P.
FKJ. 5<S. Orthosoma net/ in.
bnin-
the straight -bodied
a beetle with lon horns.
Prionid. Brown color. Nat. size. Photo, by W. H. C. P.
2 Figs. 57 and 58.
3 chrysomela, gold beetle, from xPVffb*> gold, and /^Xoy, apple.
THE BEETLE AND ITS ALLIES
55
States is the ten-lined Colorado potato-beetle, Doryplwra1 decemlineata. Until about 1859 this species fed upon the sand-bur {Solatium rostratmiri), at the eastern base of the Rocky Mountains and south into Mexico. With the advent of settlers and the plant- ing of the cultivated potato (Solanum tuberosum, a native of Mexico), this more thrifty, cultivated species was adopted as its food-plant, and the potato-beetle began its eastern migration. It spread slowly at first, but within fifteen years had reached the Atlantic coast. The little red, yellow, and black asparagus-beetle, the yellow, black-striped cucumber and melon beetle, the tortoise-beetle, whose broad, iridescent, translucent elytra are conspicuous on the leaves of the morning-glory, nettle, and other plants, all belong to this family.
So long has become our list of destructive beetles that it is with satisfaction that we turn at the end to a family which is almost wholly beneficial to the vegetable kingdom, as well as to most vegetable-feeders, includ- ing man. This is the ladybird family, FIG. 59. — Coccinellidce. These beetles are preda- ceous, both in the larval and adult stages, feeding upon small insects and insect eggs (Figs. 60 and 61). They are especially active in freeing plants from scale-insects and plant-lice. So rapidly do the latter multiply that were it not for the voracious larvse of the ladybird most plants would be
1 5opv<f>6pos, spear-bearing.
robin&, the locust borer, found on the golden - rod. Photo, by W. H. C. P.
56
ZOOLOGY
destroyed in a single season. The larvte of the ladybirds are dark, spotted, and hirsute. One of the commonest of
our eastern ladybirds is a red- backed, two-spotted one (Adalia i>'' pun data).
The food of beetles is, as we have seen, extremely varied, pIG. <;i.
more varied, indeed, than that of Anbtisocel- FIG. CO.— Pupa of ,, if-- lata. Adult.
Aiiatisvcellutaon anJ Other Order Ot insects ; WOOd- Nat. size.
a leaf. Nat. size, fibre, bark of living or dead trees, Photo- b^
Photo, by V.H.L. . , V.H.L.
leat and stem tissue, nuts, truits,
grains, insects, adult and larval and dead animals of vari- ous sorts, are all utilized by them as food. Those beetles which destroy living plants, or which feed on fruits and grains utilized by man, those which burrow in tim- ber, devour meat or articles of human industry and collections prized by man, may be ranked as economically injuri- ous. One species, indeed, is injurious as a parasite of a useful animal ; this is a curious beaver parasite, Platypsylla 1 castoria,2 In so far as certain predaceous beetles feed upon other carnivorous species of insects, as do certain tiger carrion beetles, or upon small fish,
FIG. fi2. — Platypsylla castoria, the beaver as do some of the Dytiscidse, or upon
parasite. From -• j. • i TI • -IT P.I
Packard. domestic bees, like certain allies ot the
weevils, they may be indirectly injur- ing man. Of all the families of beetles, probably the leaf- eaters cause greatest destruction ; next to them come the weevils, followed by the Cerambycidse and the others.
s, broad ; \j/v\\a, a flea.
2 Fte. 62.
THE BEETLE AND ITS ALLIES 57
Every part of the plant has its coleopterous enemy. As Le Conte and Horn have said: "As the function of the Cerarabycidse is to hold the vegetable world in check by destroying woody fibre, the Brnchidiu (weevils) effect a similar result by attacking the seeds, and the Chrysome- lidte by destroying the leaves.-"
The list of beetles directly or indirectly useful to man is small. The carrion-beetles, tumble-bugs, and rove- beetles, which feed upon decaying animal and vegetable matter, are useful as scavengers. Of those which serve us by killing other insects injurious to vegetation, the lady- bird beetle stands first. The economic importance to us of this one family can hardly be estimated. Different kinds of ladybirds feed on different species of insects. At one time it seemed that the orange industry, if not that of fruits in general, was doomed in California on account of the destruction wrought by the introduction of a scale-insect. As the insect had been imported, we had no native beetle which attacked it. Search was made abroad, and a lady- bird beetle was found in Australia which feeds on this particular scale-insect. The Australian beetle was intro- duced into California, and now the scale-insect is subdued. The larva; of some of the checkered beetles l feed upon the larvas of boring beetles, while the larva} of tiger-beetles watch at the mouth of their burrows for other insects upon which they feed. Carabid beetles are said to ascend trees in search of canker-worms. Larva} of ground-beetles prey upon the pupating plum Curculios. Other beetles eat cut- worms, and infest the common wasps.
One beetle, the blister-beetle, known in the markets as
1 A family of rather small beetles, living in flowers and on trees, and
often with, contrasting colors.
58 ZOOLOGY
the Spanish fly, has been for ages used as a drug. When disturbed, there exudes from the joints of this insect a liquid serving as a protection, since it burns or blisters the disturber. This property is retained in the extracted or dried substance. The article sold in drug stores is ob- tained from crushing the dried beetle. The larvse of vari- ous beetles have been prized as food by certain peoples from the Romans of Pliny's time down to the present, for they are eaten with relish by certain tribes of South American Indians. Fireflies sewn in lace are sometimes worn by the Spanish and Cuban women as adornments for evening dresses, while other beetles with particularly hard and beautifully colored and iridescent wing-covers are used as settings in hat ornaments and buckles, as well as in jewels.
APPENDIX TO CHAPTER III
KEY TO THE PRINCIPAL FAMILIES OF THE COLEOPTERA
(The terminology of the key may be understood by reference to the figures
on page 59.)
a\. Hind tarsi with five segments, as likewise also usually the other tarsi, certain aquatic families excepted [Pentamera] .
T>I. Elytra, short, exposing nearly whole of abdo- men . Staphylinidce
(Rove-beetles) &o. Elytra, nearly or quite covering abdomen.
GI. Antennae bent, first segment long, ter- minating in a club made of applied lamella?.
di. Lamellae closely applied and flat- tened . LnmrtUcornia
(Lamellicoras)
dz- LamelUe not closely applied ; man- dibles very large .... Lucanidce
(Stag-beetles)
APPENDIX TO CHAPTER III
59
FIG. 62o. — Under surface of Harpalus, a ground-beetle. After Le Conte. a, lignla ; b, paraglossse ; c, supports of labial palp1 ; d, labial palp ; e, men- turn ; f, inner lobe of maxilla ; y, outer lobe of maxilla; h, maxillary palp ; i, mandible ; k, buccal open- ing; I, gula or throat; mm, buccal sutures; o, prosternum ; p', epister- num of prothorax ; p, epimeron of protborax; q, qf, qff, coxre; r, r' , >", trochauters ; s, •••', s", femora or thighs; t, t', t", tibiae ; v, V2, Vs, etc., ventral abdominal segments ; w, episterna of mesothorax (the epim- eron just behind it) ; x, meso- sternum : ?/, episternum of meta- thorax ; yf, epimeron of metathorax ; z, mctasternum.
1 1 ho leader should run to base of hibial palp, d.
FIG. 626. --Upper surface of Necro- phorus, a carrion beetle. After Le Conte. a, mandible: 6, maxillary palp; c, labrum1; d, epistome ; e, antenna ; y. vertex of head ; /;, back of head; •/, neck; /.prothorax; m, elytron; n, wing or hind wing ; o, scntel- lum (of mesothorax) ; p, dor- sal surface of metathorax; q, femur or thigh ; r, r'2, r3, etc., dorsal abdominal segments; s, s'2, .s3, etc., spiracle openings or stigmata; t, t', t', tibiae; v, tibial spurs; iv, tarsi.
1 The leader should run to the V-shaped piece in front of d.
60
ZOOLOGY
Antennae straight, or, if bent, not ter- minating in lamellate club. di. Maxillary palp as long as or longer
than antennae . HydrophilidoB
( Water-scavengers ) dz- Maxillary palp clearly shorter than
antennae.
d. Six to seven ventral segments, or if only five, the first 3 or 4 are grown together, /i. Anterior coxse spherical or transverse, projecting little from the coxal cavity.
<7i. All legs used in run- ning or walking . Carabidce
(Eunners)
g.2. At least the hinder legs used for swim- ming
/2. Anterior coxse conical or tooth-like, projecting prominently from coxal cavities.
gi. Anterior coxse coni- cal ; abdomen com- posed of six rings .
~] DytiscidoB
(Divers)
i Gyrinidw
} (Whirligigs)
Silphidas
(Carrion-beetles)
ffz-
Anterior coxas ap- proximately cylin- drical ; c u t i c u 1 a soft, leathery
Abdomen composed of five rings.
/i. Anterior coxas spherical ;
prothorax with a pro-
cess resting in a depres-
sion of the mesothorax.
gi. Not capable of leaping
into the air
Lampyridce
(Fireflies)
Buprestidce
(Metallic Wood-borers)
APPENDIX TO CHAPTER III 61
gr2. Capable of leaping into
the air . . Elateridai
(Click-beetles)
/2. Anterior coxae conical, pro- truding from coxal cavi- ties .... Dermestidai
(Dermesticls) Hinder tarsi 4-jointed ; anterior and posterior
tarsi, 5-jointed [Heteromera]. &i. Fore coxse separated, more or less enclosed in
coxal cavity Tenebrionidcv
(Meal-beetles)
b-2- Fore coxae near together, protruding ; neck evident ; elytra broader than attachment to thorax ....... Meloidce
(Blister-beetles)
Tarsi apparently 4-jointed, really 5-jointed, with very small, hidden, penultimate segment [Cryp- topentamera] .
61. Head drawn out into proboscis . . . Curculionidcv
(Snout-beetles)
62. Head not drawn out into proboscis.
Ci. Head prominent ; antennae usually as
long as or longer than body . . Ccrambycida.'
(Long-horns)
c2. Head short, sunk in thorax.
d\. Antennae short, bent, with thick
terminal knob .... Svolytidm
(Engravers)
<?2. AntennaB thread-like or beaded . Chrysomelidce
(Leap-beetles)
Hind tarsi apparently 3-jointed, really 4-jointed, with inconspicuous penultimate joint [Crypto- tetraniera]. Short head, without clearly marked-
off thoracic shield Coccinellidce
(Ladybirds)
CHAPTER IV
THE FLY AND ITS ALLIES
THE term "fly" is applied to many of the insects belong- ing to the Diptera 1 or group of two- winged insects.2 It is strictly applied to the family Muscidse.3 The most gener- ally known representatives of this family are the house-fly with a sucking mouth, the stable-fly with a mouth fitted for piercing skin and sucking blood, and the blow-fly with a steel-blue abdomen. These flies love sunshine and dry ness. On a bright day they fly actively in the open air. On damp days, on the other hand, they swarm into houses and
1 5/s, twice ; irrepbv, wing.
2 The following is a key to the principal suborders of the Diptera : —
ai. All three thoracic segments fused, usually winged ;
under lip unsegmented. 61. Adults not parasitic ; maxilla; covered by upper
lip. d. Antennae long, many-jointed . . . Ncmatocera
(Gnats and Midgets; c2. Antenme short, usually 3-jointed ; the third
joint ringed Bracliycera
(Flies) 62- Adults parasitic ; upper lip enveloped by max-
illse as by a sheath Pupipara
(Ex. Sheep-tick) «2. The three thoracic segments separate, no wings,
under lip segmented . . Aphaniptera
(Fleas)
3 musca, fly.
62
THE FLY AND ITS ALLIES 63
stables to avoid the wet, and otherwise show so great a sensitiveness to moisture that we predict rain by their stickiness and general increased ability to annoy. Both the house-fly and the stable-fly are abundant about stables, where their eggs are laid, and also about household pro- visions.
The different species of flies require different kinds of food, and the food of the larvae is usually different from that of the adult. Thus the larva of the house-fly develops in horse manure and various other kinds of filth, while the adult feeds chiefly upon fluids or substances which can be dissolved by their saliva and then sucked up. The larva of the stable-fly lives in and feeds upon horse manure. The adult sucks blood. The larvae of the blow-fly develop in meat, cheese, or nitrogenous vegetable material.
The development of flies is rapid. One or two hundred eggs may be laid by a single individual. These, in warm weather, hatch in a few hours into larvae, commonly called " maggots." The larvae are wholly footless, and even the head is only a slightly developed structure. The larvae acquire full size in about a week ; pupate and hatch about a week later. The process of pupation is a complicated one, for all the larval organs, excepting certain patches of tissue, are destroyed. By the growth of these patches the individual is formed anew. These changes are all deep lying, and nothing seems more passive than the brown pupal case. Finally the case breaks at one end, and the fully formed fly emerges. The metamorphosis which the fly has just undergone is a complete one.
The larvae as well as the adult flies breathe, like other insects, by means of a system of air-tubes, which begin with slits in the body wall, stigmata, and pass inward to
64 ZOOLOGY
all parts of the body- -the muscles ami all other internal organs. These air-tubes are called trachea. They can be seen best in some aquatic larvae with the aid of a strong magnifying-glass. Air is driven in and out of these tubes by means of expansions and contractions of the body wall.
Although so very numerous, flies would be still greater pests if it were not for the fact that they are preyed upon by various parasitic animals and plants. The larva of the house-fly is sometimes infested by minute hymenopterous parasites. A still more important foe is a minute plant - a fungus called Empusa1 muscce2- -which infests house- flies in the autumn. The dead flies may often be seen on window panes with fine white threads sticking out of the body, and surrounded by a halo made up of the spores discharged from the fungus upon the glass.
The order Diptera is a large one and a difficult one to study, for it contains many species and many of the species are composed of small individuals which are comparatively unknown. The members of the group can usually be distinguished by having only two wings, the posterior pair being rudimentary and transformed into knobbed " balancers." An account of the principal fami- lies follows.
The short-horned Diptera (Brachycera3), to which family the house-fly belongs, includes flies in which the third seg- ment of the antenme is unsegmented, called true Brachy- cera, and flies in which the third segment of the antennae is segmented, called anomalous Brachycera. The true Brachycera include, besides the common flies, several other common or especially interesting flies.
a hobgoblin. 2 Of a fly.
i'S, short ; /ce'pas, horn or antenna.
THE FLY AND ITS ALLIES
65
A member of the family Muscidse, which is especially destructive in tropical Africa, is the tsetse-fly (Fig. 63). The bite of this fly is so dangerous that horses and dogs cannot penetrate the region infested by it. Even herds of cattle may be killed by this fly. Consequently travellers have been hindered in penetrating into this country, and the opening up of tropical Africa to agriculture and com- merce has been much interfered with. The injurious
FIG. 63. — Glossina morixtans, the tsetse-fly. From the " Standard Natural History."
FIG. Gi. — Syrphus. Packard.
From
effect of the bite of this fly is due to a parasite introduced by it into the body of the victim.
Another destructive family includes the bot-flies (CEstii- dte1), which have a general resemblance to honey-bees or bumblebees. Their larvae are parasitic in mammals. Of this family the bot-fly of the horse, Grastropkilus 2 equif is the most generally known. These flies hover about the legs of horses and lay their eggs upon the horse's hair. The larvse, irritating the horse's skin, are licked by the horse into its mouth and swallowed. In the stomach or
1 o/crrpos, gadfly.
F
2 7CKTT77/), belly ; 0tAe'w, to like.
3 Of the horse.
66
ZOOLOGY
intestine of the horse they get abundant food, and there they develop. The larvae of another species, u the ox- warble " or "grubs," are taken into the mouth of cattle, and live for a time in the oesophagus. Then they bore their way through the walls of this tube, and travel on until they make their way out through the skin to the surface. Another injurious species is the sheep bot-fly, whose larvae cause " staggers ' in sheep.
The Syrphidae,1 like the bot-flies, mimic honey-bees, bumblebees, and wasps.2 The adults feed on the pollen and nectar of flowers, and even imitate the humming of the bee. The larvse of some forms feed upon plant-lice ; others, upon decaying vegetable matter. They may occupy the nests of various stinging Hymenoptera. The larvee of some species are known as rat-tailed maggots on account
of their having a characteristic append- age. These are sometimes found floating in foul water or even in salt water.
The robber-flies (Asilidse 3) are usually of large size, have a short head, prominent eyes, legs covered with stiff hairs, and abdomen either long and slender (Fig. 65), or stout. These flies attack and de-
FIG. 65. --Bobber- tj fl>es ^ insects mucll
Hy. Nat. size.
Photo, by AV. H. larger than themselves, such as bumble-
f P
bees and dragon-flies.
The horse-flies (Tabauiclse4) include the large mourning horse-fly, Tabanus astratus, which is of a uniform black color, the white-lined Tabanus, T. lineola (Fig. 66), and the smaller golden-headed horse and ox flies with banded
crvp<f>6s or o-ep0os, a small winged insect.
- Fig. 04.
3 From asihts, a gadfly.
From tabanus, the gadfly of Pliny.
THE FLY AND ITS ALLTES
67
wings (Fig. 67). Only the female sucks blood, while the male feeds in flowers. They are powerful and rapid fliers. The larvae are carnivorous and live in the earth or water.
FIG. 66.--Tdbanus Ihieola, white- lined horse -fly. X 1.2. Photo, by W. H. C. P.
FIG. <>7. — Chrysops, handed horse- fly. X 1.5. Photo, by W. H. C. P.
The black-flies (Simuliidse r) are representatives of the long-horned flies (Nematocera). They are familiar pests in the forests of our Northern country. The females, which alone suck blood, occur in such num- bers and are so active that they render certain places almost uninhabitable to man. Their bite often produces wide- spreading and painful inflammation, accompanied by swelling (Fig. 68). The larvse are aquatic. The Southern black-fly or " buffalo gnat ' sometimes causes the death of domestic animals.
The gall-gnats (Cecidomyidse 2) are minute flies which lay eggs on plants. The larva? make their way into the plant tissue, and cause the further de- velopment of the tissue to be abnormal, so that excrescences
FIG. (J8. — Simulium, the black-fly. En- larged. From Packard.
1 From shmtl, together ; or simultas, a hostile encounter.
2 KTJKI'S, gall-apple ; /xi»?a, fly.
68
ZOOLOGY
or galls are produced. The galls are formed only in grow- ing tissue such as the tips of branches, buds of flowers or growing leaves, and are less striking on the whole than the galls of Hemiptera (Fig. 69). A certain kind of gall-fly, called Hessian-fly (Fig. TO), is extremely injurious to wheat
FIG. (>'-.). -- Plant galls produced by Hemiptera and Diptera. 1. Pine-apple on twigs of the spruce fir produced by the spruce-gall Aphis (U/iennes abretis, one of the Hemiptera). 2. Covering gall on the petiole of the pyra- midal poplar (Populus pyramidalis), produced by Pemphigus burxarius, one of the Hemiptera. :>. Covering galls on an ash leaf (Fraxinus excelsior) , produced by Diploxi-t bnftdaria (Diptera). 4. Covering gall on Pistacia (Pisfacia lentiscu.fi}, produced by PenipJiif/ii* rornii'tdarhifi. 5. Solid galls ou the cortex of Dnvana lonyifolifi, produced by Cecidoxes eremite (Hemip- tera) . (>. Longitudinal section of one of these galls. 7. Capsule galls on the leaf of the turkey oak (Quercus cerris, Hemiptera), produced by Cecidomyia cerri*. 8. One of these galls cut through, with the operculum still firmly attached. 9. The same, with the operculum falling away ; X 3. The remain- ing figures natural size. From Kerner, " Pflanzen Leben."
THE FLY AND ITS ALLIES
69
because it infests wheat seedlings and so weakens them that
they produce no grain. Other minute gnats or midges
are destructive to clover in
the United States, either by
binding the leaves together
and sucking the sap of the
plant or by destroying the
young seed.
The mosquitoes, or Culicidse,1
are so well known that it is
hardly necessary to describe
them. They can always be F -
identified by the feathery an- tennae, by the presence of a
fringe of hairs on the hind margin of the wing, and by the
fact that the marginal vein runs all around the periphery of
the wing. The larvae are usually aquatic, but some species which are abun- dant on our Western arid plains must breed in the earth. The eggs of the aquatic species are laid in a boat-shaped mass, which floats on the surface of the
— Cecidomyia, the Hessian- fly. <i, larva; b, pupa. From the '• Standard Natural History."
B
FIG. 71.— Culex, the mosquito. A, larva; c, its respiratory tube. B, pupa; cl, the respiratory tubes; a, the end of the
niing appendages, dorsal view. After drawing of E. Burgess.
water. The larvae escape
abdomen with the two oar-like swim- from the lower ends of the
egg-cases, and are known as "wi skiers." The larvse
o o
rest vertically near the surface of the water, head downward, with the tail end' of the body at the surface of the water, 1 Culex was Pliny's name for the fly.
70
ZOOLOGY
since respiration takes place at that end (Fig. 71, A, <?). Upon emerging from the water, the mosquito floats in its pupal skin until its legs and wings harden. Since a dis- turbance in the water at this time would jeopardize the life of the mosquito, this insect always breeds in quiet waters. From the habits of the larvre, it follows that they can be easily killed while in the pond by pouring kerosene oil on the water, for this forms a film on the surface and
FKJ. Tl. — A crane-fly. Nat. size. Photo, by W. H. C. P.
prevents respiration. The objection to this treatment, how- ever, is that most of the other aquatic organisms also are killed by it.
The crane-flies (Tipulidse1) look like mosquitoes, but can easily be distinguished from them by the fact that they have a V-shaped suture on the back of the thorax. They are larger, and have relatively longer legs than the
1 tipula, among the Latins an insect which courses rapidly on the water, — a water-spider.
THE FLY ASD ITS ALLIES 71
mosquito. Their legs are easily broken, and seem to be so much in the way that flight is clumsy. The adults are quite harmless, but some of the larvae are destructive in that they feed upon tender plants and cause them to wither and die.
There remain to be considered a number of degenerate flies-- degenerate because parasitic in the adult state. The first family we may consider is that of the louse-flies,1 or Hippoboscidae.2 These small insects have a firm proboscis used for piercing, and stout legs. Only certain of the genera develop wings, and some of these lose them after they gain their hosts. They live, like lice, in the fur of mammals or the feathers of birds. They are viviparous, the larvae being ready to pupate at the time of birth. The sheep-tick, Melophagus3 ovinusf is one of the best-known forms. Diptera allied to the foregoing live as parasites on the body of the honey-bee.
Fleas (Aphaniptera 5) are likewise wingless, blood-suck- ing parasites. The body is laterally compressed so that it can move easily among the hairs of its host. The hind- ermost legs are strongest, and are used in springing. In Europe the human flea, PulexQ irritans? is a common pest, but in this country the dog or cat flea is the one which causes most inconvenience to man. The dog flea differs from Pulex irritant in having a row of tooth-like spines on the lower margin of the head. The fleas develop in dust in the cracks of the floor and about the sleeping-places of domestic pets. They may be combated by means of clean- liness and Persian insect powder.
1 Suborder Pupipara. 4 Relating to sheep (ow's).
2 I'TTTTOS, horse ; /Socr/cw, to feed. 5 d^ai/Tjs, invisible ; irrepov, wing.
3 (JLT)\OV, sheep (wool) ; ^(£70;, to eat. 6 Flea. 7 Irritating.
72 ZOOLOGY
Diptera affect man directly in very diverse ways. House-flies, black-flies, mosquitoes, and fleas are a positive source of discomfort, and often of disease. Thus there is a minute round worm, Filar ia l hominis? allied to the vinegar eel, which thrives as a parasite in the blood-vessels of men living in the tropics. The existence of this parasite, it is believed, depends upon the mosquito. The embryos are found in the surface circulation only at night, during which time man is most defenceless toward the mosquito. The embryos of the Filaria which have been sucked out of the blood by the mosquito develop in its alimentary tract, later they are deposited in stagnant water with the eggs of the mosquito, and reach man's body again if the water be drunk by him.
It is a current scientific belief that house-flies, whose larval stages are often spent in filth, which also the egg- laying females visit, are an important agent in the distribu- tion of disease. At least the suspicion is strong enough to justify all care taken to exclude flies from contact with food.
Indirectly Diptera are injurious to man by attacking domestic animals and cultivated plants. Thus the tsetse- fly is a menace to the commerce of a large part of a conti- nent. The horse-fly, the horn-fly, which worries cattle, the buffalo-gnat, which worries or even kills domestic animals, and the dangerous bot-fly, are all causes of great loss to industry. Also we have seen that the larvae of some flies infest vegetables, -- such as cabbage, radish, cauliflower, onion,- -as well as various fruits, and cause great damage. The gall-gnats destroy clover and its seed ; and, worst of all, the Hessian-fly infests wheat and Indian corn. This last-named scourge, so called because of a tradition that it
«D
1 filum, thread. 2 Of man.
THE FLY AND ITS ALLIES 73
was imported in the straw bedding of the troop-ships which brought over the Hessian mercenaries in 1775, has spread, within a century, over the eastern half of the United States, and has at various times injured the wheat crop to the value of millions of dollars. The larvae of certain Muscidse, especially the genus Chlorops,1 attack, in Europe, the stems, leaves, and ears of wheat, rye, and barley, and cause in some years great destruction, especially in Scan- dinavia.
Over against the injury wrought by the Diptera may be placed certain benefits bestowed by them. In the first rank come certain species which prey upon injurious insects, either in the larval or adult stage. The robber-flies prey on the Diptera, Hymenoptera, and certain beetles, but they are not careful to choose alone injurious species. The larvae of the Syrphidse prey on the injurious plant-lice; those of horse-flies are carnivorous, and feed on insect larvae. The larvae of certain small flies are internal parasites of bugs, beetles, and other (mostly injurious) insects ; while those of various other Diptera are useful in acting as scav- engers, — mosquito larvae, for example, serve in this way. The carrion-fly devours putrid animal substances, which might otherwise be a source of discomfort or disease. The insects which feed on decaying vegetable matter are also not to be despised. Finally, the larvae of some crane-flies, robber-flies, and Syrphidse, by boring into rotten wood, help in the work of forming forest mould. The Diptera, like almost every other insect group, has its economically injurious and beneficial species, and it is impossible to say whether mankind would be better or worse off were the group to be exterminated.
green ; cfy, eye.
CHAPTER V
LITHOBIUS AND ITS ALLIES
LITHOBIUS is a representative of the group Myriapoda,1 which are air-breathing, wingless Arthropods, closely allied to insects.2 In the body only two regions, head and trunk, can be distinguished ; the head bears one pair of antennae, a pair of jaws, and one or two pairs of maxilhe. Every segment bears legs. Myriapods differ from insects, then, in that they have no legless abdomen.
Myriapods fall into two principal groups,- -Chilopoda3 and Diplopoda.4
The chilopods, or centipedes, to which group Lithobius belongs, are active and ferocious myriapods. They are especiall}r abundant in tropical countries, but thrive also in elevated, cold situations, and at least one species inhabits the caves of North America. All are terrestrial, and live in damp and dark places, especially under stones and bark, within or under decaying wood, among barn-yard refuse, in loose soil, and under fallen leaves. Chilopods feed upon living insects, mollusks, and worms, and may be useful to agriculture through the destruction of injurious
s, very many ; TTOVS, foot.
2 Keys to the principal families of the Myriapoda, and to the commoner species of Lithobius, will be found at the end of the Chapter, page 78.
3 More correctly Cheilopoda, from xe^°s, lip< and TTOVS, foot; because the mouth parts (modified feet) are partially united to form a sort of lip.
4 diTrXous, double ; TTOVS, foot ; having two pairs of feet to the segment.
74
LITHOBIUS AND ITS ALLIKS
75
insects. Lithobins has been observed to spend hours in killing an earthworm, whose juices it sucked as food. Blue-bottle flies also serve it as food while in confinement.
Lithobius1 is of world-wide
distribution, and
over one hun-
dred species are
recognized. Our
common straw-
colored, eastern
species, Litho-
bius forficatusf
is found also in
South America,
as well as over
most of Europe.
It seems to be
replaced south
of Virginia by
another species,
spinipes.
Scutigera 3 is
easily distin-
guished by its
J loilg legs ; its
hind legs, in-
deed, are longer
than its trunk.4 Our common Eastern species (rare of New York City) is about 25 centimetres long, of a light brown color, with stripes on the back.
FIG. 73. — Scutigera. Nat. size. From Wood.
FIG. 74. - peiiclra. size Leunis.
- Scolo-
Nat.
Fro in
north
and is
It is
1 Xi'0os, stone ; jSiow. to live.
3 scutum, shield ; yerere, to bear.
2 Provided with shears, forfcx.
4 Fig. 73.
76
ZOOLOGY
very active, and feeds especially on spiders. It looks some- thing like a spider itself when in rapid movement. The Scutigeras are characteristic of the tropics, where they live especially in cellars, crawling up horizontal walls.
Scolopendra 1 includes longer and stouter myriapods than Lithobins.2 To this genus belong the poisonous centipedes of tropical countries. Among these is the giant Scolo- pendra of our Southern States, South America, and the West Indies, which reaches a length of 25 centimetres or more. This animal has a poisonous bite, which is fatal to insects and other small animals, and causes pain- ful and even dangerous wounds upon man. The biting apparatus is the first pair of feet, modified to form sharp hooks, and provided with poison-glands, which open near the apex of the claw. Ac- cording to Humboldt, the Indian children of South America tear off the heads of large centipedes and eat the remaining portions.
Geophilus3 includes relatively slow-moving species, often attaining great length, having up to two hundred segments to the trunk (Fig. 75). The species are common in Europe and America. They live mostly under stones. There is a European species, G-eopliUus electricus, which is phosphorescent, FIG. 75.— Geo- shining in the dark like a glow-fly. piriius mor- Julus 4 is very different in appearance from
uC£X» -IN £Lui
size. Photo. the preceding, for it has a cylindrical body
and numerous small legs nearly concealed
beneath it. It is commonly known as "galley-worm."
o-Ko\o7T€vdpa, myriapod of Aristotle.
Fig. 74.
3 777, the earth ; 0tXew, to love.
4 t'oiAos, centipede.
LITHOB1US AND ITS ALLIES
77
FJG. 76. — Jalnn ca/m-
The members of this genus crawl rather slowly, and when at rest coil the body. When disturbed they give out a strong odor through lateral open- ings of the body. They feed on dead snails and earthworms ; some species, on ears of Indian corn or strawberries. Their eggs are laid in holes in the ground in the spring ; consequently densis. Nat. size. they may be easily dug up at this Phot0' by W-H-C-P- season. One of the common Eastern species of North America is Julus {Parajulus) canadensis, which is dark brown or black above, has sides spotted with yellow, and nearly colorless feet, and is about 20 to 25 millimetres
long (Fig. 76). Spirobolus is a large species, 10 to 12 centimetres long.
Polydesmus l includes much-flattened species, which, when disturbed, roll up spirally. P. canadensis, of the northern United States, is deep brown, with pubescent antennae. These myriapods are somewhat destructive to agricul- ture, especially to cabbage and straw- berries.
Two genera of myriapods which stand somewhat isolated deserve a
FIG. 77. - - Polydesmus . , , . . ,
canadensis (=P.serra- passing notice. Pauropus * and allied
t-us). <i.5. Photo, by genera include a few animals about w. H. c. P.
1 millimetre long, found on the moist
loam of woods. They are intermediate between chilopods and diplopods, inasmuch as they have only one pair of legs
TroXus, much ; Secr/zos, band. 2 TraO/oos, small ; TTOUS, foot,
78
ZOOLOGY
to a segment and only one pair of maxillae. P. huxleyi occurs both in Europe and in the United States (vicinity of Boston and Philadelphia). Scolopenclrella l is a small, white species, having very large -antennae and a pair of backward-directed stylets. The mouth parts are very much like those of the lowest insects, so that Scolopenclrella bridges the gap between myriapods and true insects.
APPENDIX TO CHAPTER V
KEY TO THE PRINCIPAL FAMILIES OF THE MYRIAPODA
«i. Not more than 1 pair of feet to the segment ; much segmented antennae ; 2 pairs of maxillae [Chilopoda].
1 1. With facetted eyes ; 8 dorsal plates ; long legs . ....
1.2. "No facetted eyes, but single or aggregated
simple eyes ; 15 or more dorsal plates. Ci. 15 pairs of legs ; antennae at least ^ as long as body ; body usually with more than 20 segments
Ci. More than 21 pairs of legs.
f?i. 21 to 23 pairs of legs ; antennae more than 14-jointed
d>. Never less than 30 pairs of legs ; antennae 14-jointed .
Most of the segments with 2 pairs of legs ; an- tennae with 5 to 8 segments ; 1 pair of maxillae [Diplopoda].
l>\. Anus in penultimate segment ; body covered with bunches of hairs ....
1 Diminutive of Scolopendra.
Scutigeridce
(Ex. Scutigera)
Lithobiidce
(Ex. Lithobius)
Scolopemlridw
(Ex. Scolopemlni)
Greophilidce
(Ex. Geophilus)
Polyxenidce.
APPENDIX TO CHAP TEE V 70
Anus in ultimate segment ; body without
bunches of hairs, d. Mandibles not rudimentary ; mouth
parts not suctorial. d\. Segments 80 or more.
e\. Anal segment produced into
a spine .... Julidce
(Ex. Julus)
e2. Anal segments produced into 2 slender papilhe, or uni- dentate .... Craspedosomidce d-2. Segments 19 or 20 ... Polydesmidce
(Ex. Polydesmus) Co. Mandibles rudimentary, mouth parts
reduced Polyzoniidw
KEY TO COMMONER SPECIES OF THE GENUS LITHOBIUS
a\. Posterior angles of none of dorsal plates pro- duced ; pores on coxae uniseriate. b\. Anal feet armed with 1 spine ; posterior coxae unarmed ; spines of first pair of feet, 2, 2, 2-2, 3, 2 (Central States) . . . bilabiatits
b-2. Anal feet armed with 3 spines ; coxse with indistinct spine ; spines of first pair feet, 2, 3, 2 (Central States) .... cardinalis
«2. Posterior angle of the 9, 11, 13 dorsal plates pro- duced ; antennae, 33-43 joints (eastern U.S.) forficatus «3. Posterior angle of the 7, 9, 11, 13 dorsal plates produced ; 31-38 joints of antennae (southern U.S.) . . . . . . . . spinipes
«4. Posterior angle of the 6, 7, 9, 11, 13 dorsal plates produced ; joints of antennae, 14.-23 (eastern U.S.) multidentatus
CHAPTER VI
THE SPIDER AND ITS ALLIES
SPIDERS constitute a well-defined group called Araneina,1 characterized by an unsegmented cephalothorax and abdo- men, of which the latter is stalked, and bears spinning tubercles or spinnerets upon its hinder end. Antennae are absent. The first pair of mouth appendages are called chelicerse and end in claws, at whose apices the poison- glands open to the exterior. The second pair of mouth parts, called pedipalps, are long, and seem to take the place of antennae. Near the stalk of the abdomen on the ventral side is a pair of slits which open into two lung sacks (hence Dipneumones). In a few spiders there is a second pair of slits; these spiders have four lung sacs (hence Tetrapne union es).2
The best known of our spiders are the orb web-spinning garden spiders, belonging chiefly to the genera Epiera3 or Argiope 4 and the house cobweb spinning spider Theridium.5
Argiope spins webs of very geometric form between stems of weeds, Branches of shrubs, or along fences in our meadows.6 Its web belongs to the full-orb type in
fa, spider.
2 A key to the seven subdivisions of the Araneina will be found at the end of this Chapter, page 95.
3 e/uLireipos, skilful, experienced.
4 Name of a nymph. '° eypidiov, a little wild animal. 6 Fig. 78.
80
THE SPIDER AND ITS ALLIES
81
contrast to the condition in other orb-spinners, in which a sector of the circle is omitted or in which a sector only is formed. At the centre of the web of Argiope there is an oval, closely woven shield of silk. The spider, when at rest, is usually found upon or under this shield. Another frequent character of the web is a zigzag ribbon, extending
FIG. 78. — Web of Argiope, placed horizontally over a fish-way.
by W. H. C. P.
Photo.
downward from the central shield, and sometimes upward also, and attached to two or more radii. This zigzag, which is doubtless the "winding1 stair' referred to in
O
the rhyme, " The Spider and the Fly," is formed, as Fig. 79 shows, by preventing the fusion of the strands as they emerge from the spinnerets.
G
82
ZOOLOGY
The genus Theridium and its allied genera constitute the most extensive family found in the United States. The spiders belonging to the family are small, with relatively large, rounded abdomens. They have eight eyes, arranged in the manner shown in the diagram, Fig. 80. Their webs
show no attempt at geometric arrangement, such as is seen in the web of Argiope and other orb-weavers, but the threads cross in every direction, forming a sort of intricate trestle- work. The species Theridium tepidario ni ui is the common little cobweb-spinner of our houses and barns ; it also spins about fences. Its color varies from a livid white to a livid brown or plumbeous color. In the south this species
FIG. <9. — Argiope spinning the "winding stair." The numbers 1, 2, 3, 4, indicate IS much preyed upon
points successively formed in the order of b mud-daubillff wasps these numerals. From McCook. °
(Sphex1), which put
twenty to thirty of them in each cell of the nest as food for the young. Probably this enemy is one of the causes that has driven this species to the homes of man.
Food. — Both Argiope and Theridium feed upon insects. Flies, bees, grasshoppers, etc., are caught in the web and
wasp.
THE SPIDER AND ITS ALLIES 83
bound up, either for immediate or future consumption. A few authentic instances have been recorded of the capture of mice by ordinary spiders, and some tropical 0 0 0 0 spiders are said to capture occasionally small 0 0 birds within their webs. All spiders eat FIG. so. — Dia-
, , ,. ., 1-1 gram of posi-
voraciously, and ordinarily drink a great tkmof eyes in deal of water; yet they may survive, in Theridium.
J The four cen-
tne absence 01 rood ana water, tor many trai eyes are
months. the largest.
Distribution. — Argiope occurs over all of North America. A. cophinaria, the basket Argiope, is the large black and yellow spider well known to all frequenters of Melds. It occurs from Massachusetts to Texas, and west to the Pacific coast. A. argent at a, distinguished by the serrated form of the abdomen, is found in the Southern States, the West Indies, and northern South America. Theridium occurs all over the world. T. tepidariorum is found, outside of the United States, in South America, Europe, and Australia. Twelve other species of this genus are found in New England alone. Some of these spin webs in trees or bushes, others in stone walls or among rocks.
Spinning Habits. - - Spiders spin for a variety of purposes. Cocoons are made of silk, for the protection of eggs ; under- ground nests, like that of the trap-door spider, are lined with silk ; and, especially, nets are made of it to ensnare insects. The silky threads may serve also to suspend the spider while it drops from a tree, or they may, by their friction with the air, serve to suspend certain spiders in aerial migrations.1 This latter use is especially noteworthy.
1 The ballooning habit of spiders has been noticed since early times, but it was formerly misinterpreted. Thus Pliny speaks of wool being rained. The poet Spenser wrote : —
84
ZOOLOGY
A small spider, when desirous of taking flight, climbs up some high object, such as a fence post, elevates the spin- nerets, and spins loose silk into the air (Fig. 81). After enough of it has been thus formed, the spider lets go, and is supported by the currents in the air while it is wafted great distances. Thus Darwin, on his voyage in the Beagle, saw cobwebs bearing up spiders floating in the
air over his vessel more than sixty miles from shore.
The method of spinning deserves careful attention. The spinning-organs consist of a set of glands lying in the hinder part of the abdomen, and opening to the exterior through a number — - often several hundred --of spin- ning "spools." These spools are the modified mouths of glands, and are grouped upon and between tubercles called spinnerets. The secretions of the glands, as they are poured out into the air, fuse together and
harden into a thread. The thickness of the thread is determined by the number of glands secreting together.
" More subtle web Arachne cannot spin ; Nor the fine nets, which oft we woven see, Of scorched dew, do not in th' ayre more lightly flee."
Thompson writes : —
" How still the breeze ! save what the filmy threads Of dew evaporate brushes from the plain."
THE SPIDKU AND ITS ALLIED
85
Classification. - -Spiders are separated, according as they spin webs or do not do so, into two main groups, sedentary and wandering spiders. The sedentary spiders are sub- divided into four sub-orders, which we shall consider in turn : —
FIG. 82. — Mygale, a Tunnel-weaver, allied to the " trap-door spider."
Nat. size. From Emerton.
1. Tunnel- weavers (Territelarite 1). These spiders make tubes in the earth, and line them with silk. The repre- sentatives of this group in the Southwestern States are
1 terra, earth ; tela, tissue or web.
86
ZOOLOGY
commonly known as trap-door spiders. The lid of the nest is covered with hardened dirt, and when closed, looks
exactly like the ground around
FG it. Some of these spiders gain
a great size and capture birds (Fig. 82).
2. Orb-weavers (Orbite- lariee 1). These, which are typically represented by Argiope, are well known ; yet few persons have studied the almost mathematical precision with which the webs are built. Foundation lines (Fig. 83) of unusual strength are first laid down, to form the periph- ery or frame of the web. Then radii are spun from a central little ball of floss to the frame. The radii are, often at least, laid down alternately on opposite sides of the centre. The number of radii formed by a species of spider is not perfectly constant, but varies within limits. It would be an interesting occupation to sketch a number of webs of Argiope showing the variations in the number of radii and the other details of form. After the radii are placed, the spiral lines are laid down. In the completed web four regions are distinguishable, as follows, passing from the centre outward : (1) the notched zone, consist- ing of four to eight turns of a spiral at the centre ; (2) the free zone in which no spiral is laid down ; (3) the spiral space, the main part of the spiral framework ; (4) the
1 orbis, circle ; tela, web.
rs
FIG. 83. — Diagram on nomencla- ture of parts of an orb-web. FS, foundation space ; SS, spiral space; CS, central space ; FZ, free zone ; NZ, notched zone ; H, centre. From McCook.
THE SPIDER AXD ITS ALLIES
87
foundation space, without the spiral lines, and at the outer margin of the web. No study is more interesting than that of the details of construction of these parts of the spider web, while they are being made out of doors or in large glass jars.
FIG. 84. — Orb-web of Epeira. a, first spiral line ; b, second spiral line ; c, line
to nest. From Emerton.
3. Line-weavers (Retitelarise1).- -Of this group The- ridium is a type. The web consists of a fine irregular mesh with strands running above and below in various direc- tions.2 The spider stands below the main part of the net, back downward.
1 rete, net ; tela, web. 2 Fig. 85.
88
ZOOLOGY
4. Tube- weavers (Tubitelarue 1). Here belong the spiders that spin webs in the grass, which are so conspicuous in the morning when laden with dew (Fig. 86). At one side of the web a tube leads down among the grass stems. At the opening of this tube the spider stands ready to
FIG. 85. —Web of Theridium, a " cobweb." From Emerton.
dart out after prey, or to retreat as occasion demands (Fig. 87).
The wandering spiders do not spin webs of any kind. They are classified into three groups as follows : —
1 tubus, tube ; tela, web.
THE 8PIDER AND ITS ALLIES
89
(1) Crab spiders (Laterigradse *) are so called because they run sideways. They make nests by fastening together leaves by threads of silk. Their young are reared in these nests, and watched over by the mother (Fig. 88).
('2) Running spiders (Citigradre2). - These are for the most part large and powerful species which wander over
FIG. 86. — Web of a tube-weaver; looking down upon the web, which is in a corner between two vertical walls. The tube is in the angle. Photo, by W. H. C. P.
fields or along watercourses in search of prey. Our Northern species belong chiefly to the genus Lycosa3 (Fig. 89). They live in holes in the ground, making a ring of silk at the orifice. The female carries her eggs about in a special cocoon attached to the end of the abdomen. The
j side ; gradus, locomotion. 2 citus, rapid, + yradus.
3 Xtkoj, wolf.
90
ZOOLOGY
FIG. 87. — Agalena, the common grass spider. Nat. size. Photo, by W. H. C. P.
young are borne on the back of the mother. The great size, black color, and hairiness of some of these spiders have given them an apparently unjustified reputation of being very poison- ous. Naturalists who have al- lowed these spiders to bite the hand report that the bite is rarely more poisonous than that of the mosquito.
(3) Jumping spiders (Salti- gradse 1). - This family includes many familiar, active species of
high intelligence. Some of these of grayish color live in houses, and are recognized as members of this family by their half -running, half- jumping gait (Fig. 90). The cocoon is attached to some object and enclosed in a sort of tent, in which the mother also lives to guard the young.
The economic impor- tance of spider webs is con- siderable. First of all, they are of the greatest importance in capturing many destructive insects, such as flies, mosquitoes, and moths. Another use
1 saltus, jumping, + yradus.
o
o
o o
O O
o o
FIG. 88. — Thomisus, a crab spider. Dia- gram showing arrangement of eyes at bottom of figure.
From Emertou.
THE SPIDER AND ITS ALLIES
91
to which they have been put is in making silk cloth. The silk of the spider is smoother and glossier than that of the silk-worm, but it is much harder to collect in quantity. A spool is passed against the spinnerets of an individual spider and slowly revolved, winding the silk upon it. The difficulty comes in rearing the spiders, for they are extremely voracious and if the supply of flies is insufficient
FIG. 89. — Lycosa, a running spicier. Ocelli formula below. From Emer- ton.
FIG. 90. — Attus, a jumping spider. From Emerton.
they attack and devour one another. Consequently they must be kept isolated and fed individually, and yet yield in the end only an ounce or so (about 30 grammes) of silk. Other uses of spiders' silk are : in the construction of cross-hairs in telescopes, and in medicine as a narcotic in case of fevers, - - a temporary fad.
Poisonous Spiders. — Spiders are feared by many people from a belief that they are very poisonous, even fatally so. Spiders have, indeed, biting jaws provided with poison-
92 ZOOLOGY
glands, and their bite is often fatal to insects, and even to small birds and mammals. But most spiders cannot spread the chelicene sufficiently to make a bite in the human skin, and even the largest forms seem to inflict but a slight wound, scarcely ever greater than that of a mosquito. The stories of the severe effects of the bite of the Taran- tula, one of the Lycosidse, are entirely fabulous.
Spiders show a marked sexual dimorphism. Particularly among the orb-weavers the males are much smaller than the females of the same species, but the legs of the male are relatively the longer and stronger. The male is usually shorter lived than the female, for the latter has often to watch the egg-cocoons, or carry them about with her until the young hatch out. The male also builds less perfect webs than the female. The relation existing between mated pairs is often peculiar. The male is frequently killed and eaten by the female; but if the male can over- come the female, she may fall his victim. Among wander- ing spiders there is often a selection by the female from among several rivals, which engage in severe battles with each other.
Allies of the spider must be briefly mentioned. The spider belongs to the class Arachnoidea,1 characterized as follows : Air-breathing, wingless arthropods, whose head and thorax are usually united to form a cephalothorax, which bears two pairs of jaws and four pairs of legs ; the ab- domen, which is not always separated from the cephalo- thorax, possesses no legs. The principal subdivisions of the Arachnoidea are as follows : -
The Arthrogastra,2 including the scorpions and their allies, are characterized by the fact that the abdomen is
j, spider ; eUos, form. - dpdpov, joint ; yarnf/p, abdomen.
THE SPIDER AND ITS ALLIES
93
palp.
segmented and intimately joined with the cephalothorax.1 Here belong the true scorpions, in which the posterior six segments of the abdomen are much smaller in diameter than the seven anterior segments, and form a sort of tail (post-abdomen ) . Nearly twenty species of scor- pions occur in the warmer parts of North America. Centrums in- famatus ranges from the
* O
southern Atlantic States, through Texas, and north into southern Kan- sas. The tip of the tail bears a sting, which con- nects with a poison-sac. The largest scorpions of the tropical countries are the most dangerous, but the wounds even of these are rarely fatal.
The Phalangina,2 the extremely common "Daddy-long-legs," or harvest-men, in which
the legs are very long, FlG oi.__Buthus, a European scorpion.
and the abdomen short Dorsal view. MX., maxillary; Cephth.,
, . . , rp. cephalothorax; Troch., trochanter ; Tor.s'.,
and tlllCK. hey OCCUr tarsus; AbO., abdomen ; Bla., poison blad-
aboilt houses, in woods, der; St., sting. From Kraepelin in "Das
Tierreich.'
and in fields. They
feed on small insects and are highly beneficial animals to
2 0aAd77ioj>, a spider, especially a poisonous species.
Dorsal ridge*--- Lateral ridge-'
1 Fig. 91.
94
ZOOLOGY
FIG. 92. — Liobunum dorsatum, one of the harvestmen. The long legs are apt to be thrown off in handling the living animal. The second left leg is accordingly absent in this specimen. Nat. size. Photo, by W. H. C. P.
FIG. 93. — Psoroptes, the sheep scab, female.
Right
figure, dorsal view; left
figure, ventral. Industry.
Much enlarged. After Salmon, Bulletin 21, Bureau Animal
THE SPIDER AND ITS ALLIES 95
man. Liolmnum dorsatum is a common grayish species with a darker dorsal band, which emits a clear fluid when handled (Fig. 92).
The Areneina, or spiders, already considered.
The Acarina,1 or mites and ticks, in which, as in spiders, the abdomen is unsegmented, but is fused with the cephalo- thorax. Mites have typically a round body. They exhibit great diversity of form and habits. All are terrestrial, excepting one group of aquatic mites, and are often of a bright red color (A tax). The free-living species prey on smaller animals, as well as dead organic substances. Others are parasitic in animals
, . . • f p J.T 9 i FIG. 94. — Pal-
or plants, living in fur or leathers/ and even Ien6) a sea_ penetrating into the skin, as the small red spider. : 1.5.
,, , . ,, r. 0 ,, Photo, living
"jigger or " c nigger ' or our bouthern byW.H.c. P. States does.
Finally, there lives in the sea an aberrant family of spiders which crawl on the sea-bottom or over hydroids, and thus have forsaken a terrestrial life for a completely aquatic one (Fig. 94).
APPENDIX TO CHAPTER VI
KEY TO THE SEVEN SUBORDERS OF THE ARANEIISTA
«i. With 4 slits into lung sac [Tetrapneumones]. Che- lifer claw directed downward ; 8 closely grouped
eyes Territelar!«'
(Tunnel-weavers)
a*. 2 slits into lung sac [Dipneum ones]. Chelifer claw directed inward.
i a/cct/n, mite. 2 Fig. 93.
96
ZOOLOGY
b\. Eyes in 2 transverse rows ; most species spin
webs [Sedentarise]. Ci. Legs not spread flat out.
d\. Spinnerets short and inclined together, and on under side of abdomen, which is usually round.
e\. Anterior row of eyes near margin of head
e-2. Anterior row of eyes remote from , margin of head ....
d\. Spinnerets at end of abdomen, which is elongated .....
Ci . Legs spread flat out .....
61. Eyes in 3 transverse rows ; spin no webs, but
hunt prey [Vagabundse]. Ci. Anterior eyes smallest ....
c2. The anterior eyes largest .
OrbitelaricB
(Orb-weavers)
Retiielarice
(Line-weavers)
Tubitelarice
(Tube-weavers)
Laterigradce
(Crab spiders)
CitigraddB
(Running spiders)
Saltigradce
(Jumping spiders)
CHAPTER VII
THE CRAYFISH AND ITS ALLIES
THE crayfish belongs to the class of Crustacea, since it breathes by means of gills, possesses two pairs of antennae, a pair of mandibles bearing palps, and a pair of append- ages on all body segments excepting the last. The Crustacea are divided into two subclasses,- - Entomostraca, of which Daphnia is an example, and Malacostraca, to which the crayfish belongs. All the Malacostraca 1 have 19 pairs of appendages.2
The crayfish,3 which is closely related to the marine lobster,4 is an inhabitant of fresh-water lakes, rivers, and pools. It thrives in diverse surroundings; for some species prefer cool mountain streams and others muddy pools, while certain species, both in Europe and America, are found in brackish as well as fresh water. Indeed, the European Astacus fluviatilus is said to be frequently
s, soft ; 'ocrrpaKov, shell (since the shell is less hard than that of mollusks).
2 Keys to the six chief orders of Malacostraca and to families of the stalk-eyed Crustacea will be found in the Appendix to this Chapter, p. 122.
3 The old English spelling of this word was ''crevis'' or "crevice." The ere came to be spelled phonetically cm//, while vis became changed to fisli in accordance with the popular nomenclature of all aquatic animals.
4 The English word " lobster " is from the old English lopystre, which is probably corrupted from the Latin locusta, by which term Pliny refers to the lobster.
H 97
98 ZOOLOGY
caught off the Livoniaii coast, even some distance out at sea. Individuals of an American species have been taken from a mineral spring impregnated with sulphur and magnesia at a temperature of 70° Fahr. (21° Cent.), while several kinds of the American "burrowing' or " chimney "-forming species have been found in meadows and clay bottoms, often at great distances from streams. Certain species that are blind inhabit caves only. In England, according to Huxley, "in granite districts, and others in which the soil yields little or no calcareous
ty
matters to the water which flows over it, crayfishes do not occur. They are intolerant of great heat or of much sun- shine ; hence they are most abundant in those parts of rivers which flow east and west, and thus yield the most shade from the midday sun."
The food of the crayfish is very varied ; it may be living or dead, animal or plant. On account of the need of calcareous matters in the food, crayfishes are especially fond of the stoneworts (Chara) and various succulent roots, like the carrot. It is said that crayfishes sometimes make excursions inland in search of plant food. They likewise devour shells of snails, their own cast-off skins, and occasionally each other, shell and all.
There are two great groups or subfamilies of cray- fishes. One, restricted to the Northern Hemisphere, is found in Europe, Asia, and North America. The other is found in the Southern Hemisphere, in Australia, Tasmania, New Zealand, Fiji Islands, Madagascar, and South America. No crayfishes have been found on the continent of Africa, or in the rivers of northern Asia that flow into the Arctic Ocean, or in those of southern Asia. These Asiatic rivers are populated by fluviatile crabs, to which the cray-
THE cnAYFixrr AND ITS ALLIES 99
fishes of the region have probably succumbed. All the islands now inhabited by crayfishes, such as England. Japan, and Cuba,1 were probably once connected with the mainland.
The northern subfamily of crayfishes contains, accord- ing to Faxon, two genera- -Astacus and Cambarus- -of which the latter can be subdivided into the subgenera Cambarus and Cambaroides. These groups occupy dis- tinct geographical areas. The genus Astacus is found, in the Old World, in Europe and western Asia as far south as the Aral and Caspian seas, and in America in the region west of the Rocky Mountains, draining into the Great Salt Lake and the Pacific Ocean. It is thus seen to occupy the western sides of the two northern continents. Likewise Cambarus and Cambaroides occupy the two eastern coasts of the northern continents; for Cambarus is found in North America east of the Rocky Mountains in the region bounded on the north by Lake Winnipeg and New Bruns- wick and on the south by Guatemala and Cuba, while Cambaroides is limited to the Amoor River basin in Asia, and to Japan.
We thus find among the crayfishes what is known as discontinuous genera; that is, genera which now occupy widely separated areas, such as Astacus in Europe and Pacific North America, but which once ranged over the intervening regions as well. From some cause, the struggle for existence became too severe in the intervening regions, so that Astacus and Cambarus were annihilated on the eastern and western sides of the continents respectively. In southern Asia we find that the struggle was doubtless with the successful river-crab. It is interesting to note
1 It is doubtful whether Cuba has been connected with the mainland.
100 ZOOLOGY
that, probably on account of the preserving influence of climate, the other animals and the plants of the eastern sides of the two continents and those of the western sides are more alike than those from opposite sides of the same continent. One of the best pieces of evidence for the con- clusion of a former hemispherical distribution of the two genera of crayfishes is that there occur in the caves of Carniola in southern Austria crayfishes l belonging to the genus Cambarus - - the only known living representatives of this type in Europe. The mere fact that it lives in a cave is not sufficient to make the Carniola crayfish a Cam- barus, for in North America the genus has certainly not originated under the influence of subterranean life ; it is more likely that the caves of Carniola have protected these crayfish from the widespread destruction which has over- whelmed their fellows outside.
Only one crayfish, Cambarus Bartonii, is found in New England., and here, with two or three local exceptions, only in the rivers of Maine. This C. Bartonii has the widest geographical distribution of all the northern species. C. Blanding'd is the most widely distributed of the southern species. C. pellucides is the blind species found in Mammoth and Wyandotte caves.
The lobster (Homarus) is, as we have already seen, the nearest living salt-water relative of the crayfish. There are only two species of the genus Homarus. One, Homarus americanus, occurs on our Atlantic coast, the other, H. vulyaris, is the lobster of Europe. On our Pacific coast there is the "spiny lobster," but this is not closely related to the eastern lobster (Fig. 95). The national gov-
1 These crayfishes are blind, like the cave-inhabiting Cambarus of America.
THE CRAYFISH AND ITS ALLIES
101
eminent has transplanted the Atlantic lobster to several localities on the Pacific coast, but it is not yet known whether it will thrive there. The American lobster ranges from Labrador to Delaware Bay, and from near shore to a
FIG. 95. — Palinurus, the spiny lobster. One-fourth nat . size. From Rathbun ;
drawn by H. L. Todd.
depth of 100 fathoms. It attains its greatest size on the rocky shores in the cooler waters from Maine to Labrador. It migrates but little along the coast ; in the fall, however, it moves out into deep water, and in the spring back again
102 ZOOLOGY
into the shallower bays ; the time of migration depending upon the length of the season. It is said to be a nocturnal animal, searching most actively for its food at night. The sense which probably aids it most in this search is that of smell, as the attraction of the bait in the traps - - the so- called lobster-pots — testifies. In respect to food it is, like the crayfish, omnivorous.
Protection of the Lobster. — There has been much differ- ence of opinion in regard to the size at which a lobster becomes mature and before which, therefore, it cannot be caught without danger of extermination. The legislation on the matter has accordingly been very varied. In Con- necticut the law makes the limit six inches, while in Massachusetts and New York it is placed at ten and one- half inches. Herrick has carefully investigated the relation of length to maturity, and concludes that, on the Massa- chusetts coast at least, the lobster becomes mature between the limits of eight and twelve inches, and hence that all present legislative protection is insufficient. The increasing rarity of large lobsters in our markets testifies to the correctness of this conclusion.
Enemies of the Lobster. — Besides its worst enemy, man, both the adult (particularly the egg-bearing female, called by fishermen the " berry lobster," or "berry hen") and young lobsters are attacked by many kinds of fish. Two or three internal parasites are known to infest the lobster, while sometimes it is greatly hampered in its movements by the number of messmates it; carries about attached to its shell. Barnacles, mussels, tube-forming worms, and various seaweeds are all found at times attached to the shell of the lobster. Upon moulting, however, the animal is enabled to rid itself of all these hangers-on ; but this very process of
THE ('HAY FISH AND ITS ALLIES 103
moulting, or casting off the entire shell at intervals, is attended with great dangers to the lobster, since the animal is so soft bodied as to be able to offer little resistance to its enemies.
The moulting process in the lobster, crayfish, and other Crustacea is made necessary from the fact that these animals are enclosed in a chitinous covering which is impregnated with salts of lime. It is evident that an animal cannot increase in size while so encased ; hence special provision for growth has to be made by the moulting or casting off of the hard shell. This process is accomplished in the following manner: previous to the throwing off of the old skin a new soft one is formed inside, the lime is absorbed from the old shell in a dorsal line along the carapace, reaching from the rostrum to its posterior margin. Ab- sorption also takes place at the joints of the limbs. AVhen the lobster has attained this stage it is dark in color, and known by fishermen as the " black lobster." The carapace now splits along this dorsal median line of absorption, the blood leaves the limbs, which are thus made flabbier, and by involuntary muscular movements they are drawn, large claw and all, through the joints of the old shell. The anterior portion of the body is first drawn out through the dorsal rent, and lastly the tail. Not only is the entire outer covering cast off, but the lining of the oesophagus, stomach, and intestine as well, since these organs are formed by an infolding of the skin. By means of the return of the blood to the limbs and rapid absorption of water, the body of the lobster soon swells to a size far beyond that of the old shell. There remains in the stomach, after moulting, a calcareous nodule which has long been known by the name of "crab's- eyes." These " crab's-eyes ' were formerly much sought
104 ZOOLOGY
after and prized on account of their supposed medicinal qualities. The function of these gastroliths or " craVs- eyes ' was for a long time rather obscure. It is now believed that during the time of absorption of lime from the shell, previous to moulting, the blood becomes strongly impregnated with lime. If all the lime that must be re- moved were to remain in the blood, it would probably be fatal to the animal ; hence it is taken up by secreting cells located in the wall of the stomach, and there deposited. After the old skin is cast, the gastrolith is soon absorbed,
FIG. 90. — Palasmonetes vulyaris, a common shrimp. Nat. sizo.
Photo. 'by W. H. C. P.
probably to aid in strengthening the new shell. Bits of water-worn shells, entire gastropod shells, parts of lobster coverings, spines of sea-urchins, etc., have been found in the stomachs of lobsters and crayfish, which likewise would probably have been dissolved and used in hardening the shell.
Shrimps and prawns l belong to a thin-skinned, long-tailed family of Crustacea.2 They are extremely common in bays
1 These are common names of small Crustacea applied chiefly to the decapod family Carididse,* although also applied to certain Schizopods. The term shrimp is applied to the smaller species, and prawns to the larger. 2 Fig. 90.
* (capis, a small marine crustacean.
THE CRAYFISH AND ITS ALLIES 105
along our coast, and even penetrate into rivers. Two river shrimps l are found in the United States east of the Missis- sippi River. These Crustacea are able to maintain their enormous numbers only by virtue of their great repro- ductive capacity, necessitated by the circumstance that they furnish almost the entire food supply for many kinds of fishes and other foes. Even in the principal shrimping grounds of the United States- -such as San Francisco and
FIG. 97. — Gebla affinis, right side. Two-thirds natural size. ' Photo, by W. H. C. P.
New Orleans — there is said to be no diminution in the numbers of shrimps.
The Thalassinidae 2 include certain crayfish-like species which live on our coast, burrowing in mud-flats, where they live concealed during the day. On account of their being of only medium size and difficult to obtain, they are commonly little known. Our Eastern species are Grebia affinis (Fig. 97) and Callianassa stimpsoui.
The hermit crabs (Pagurida33) occupy a position inter- mediate between the long and short tailed Decapods in
1 Palwmon Ohionis and Pal eomonetes exilipes.
2 0a\d(Tcrivos, color of the sea. 3 irdyovpos, a kind of crab.
106
ZOOLOGY
respect to the length of their abdomen. The abdomen is soft, and the animal protects it by inserting it within the coiled shell of some gastropod. Moreover, the abdomen is asymmetrical, being coiled to one side to correspond with the shape of the borrowed house (Fig. 99). The abdominal feet become degenerate, with the exception of the posterior pair, which are modified into a hook-like process, by means of which the crab maintains itself securely in the shell.
FIG. OS.
Eupagunis longicarpus. Two individuals in shells. Photo, while alive by W. H. C. P.
When one shell becomes too small, it is abandoned for a larger one. Numerous species of hermit-crabs occur on our coast, ranging from the shore line to a depth of several hundred fathoms. Eupagurus longicarpus is the little active hermit found in almost any tide-pool from Massa- chusetts Bay to the Gulf of Mexico. Hydroids, polyps, sponges, often attach themselves to these borrowed shells (Fig. 98) ; indeed, a Chinese hermit-crab always bears an anemone on its large claw, with which it plugs up the aperture when obliged to retreat within its shell. One of
THE CRAYFISH AX.D IT* ALLIED
10'
the East Indian hermit-crabs, the so-called palm-crab, feeds upon cocoanuts, Avhich it opens by inserting its claws into the eyes and then breaking the shell upon the rocks.
The Hippidae include certain oval animals, which bur- row, like a mole, head first, in sandy beaches. The name of our common eastern species, Hip pa J talpoides? indicates this resemblance ('Fig. 100).
FIG. 99. — Eupayurus lonylcurpus removed from shell, x' Ifc. Photo, by W. H. C. P.
FIG. 100. — Hippa Nat. size. Photo, by W. H. C. P.
The Brachyura are represented on our shores by three principal families, which may be designated as triangular crabs, arched crabs, and square crabs.
The spider-crabs, or sea-spiders, as they are sometimes called, belong to the triangular crabs. As their name implies, their legs are very long and slender.3 These crabs frequent oyster-beds and sea-bottoms in general. When
1 From i'TTTTos, horse ; used by Aristotle as the name of a kind of crab.
2 Like talpa, the mole.
3 Fig. 101.
108
ZOOLOGY
seen stalking over such uneven surfaces, the advantage of these stilt-like legs is at once evident. The surface of the body of some species of spider-crabs is hairy, entangling inorganic matter, while hydroids, barnacles, and algae attach themselves to the shell. Libinia emarginata and dubia^ the former ranging from Maine south, and the latter from Cape Cod to the Gulf of Mexico, are our two species which
FIG. Wl. — IJliitiin dubia. One-third nat. size. Photo, hy W. H. C. P.
undergo such concealment. The great Japanese spider- crab is said to be the largest of all the Crustacea, some individuals measuring, from tip to tip of the first pair of legs, 18 to 20 feet.
The edible crab is a typical arched crab. It is so called because the carapace is arched in front. The carapace is also broader than long, and narrower behind than in front.
THE CRAYFISH AND ITS ALLIES
109
The legs of this family are short and broad, and in some species the posterior pair is especially broad - - an adapta- tion for swimming. These crabs may be divided into two groups — the burrowing crabs and swim- ming crabs. To the burrowing crabs belongs the genus Cancer (Fig. 102), which includes the edible crab of Europe, especially prized in England, together with several American species; while our common edible, soft-shelled or blue crab, Callinectes hastatus (Fig. 103), and the beautiful "lady crab" (Fig. 104) belong to the swimming group. Representatives of other families of crabs are, however, eaten in various localities and by various peoples. For example, our little Pinnotheres
FK;. 102. - - Panopeus sayi, allied to Cancer. The mud- crab. One-half nat. size. Photo, by W.H.C.P.
FIG. 103. — Callinectes hastatus, blue crab. Reduced to one-third. Photo.
by W. H. C. P.
110
ZOOLOGY
ostreum (Fig. 105), found in the mantle chamber of the oyster, is eaten by us together with the oyster or separately.
FIG. 104. — Platyonichus ocellatus, lady oral). Reduced to one-third.
Photo, by W. H. C. P.
The fiddler crabs are representative of the square crabs. These are the familiar animals which crowd salt marshes and run sideways to and from their burrows. One claw is
much larger than the other. When the crab is disturbed, the large claw is brandished in a manner which has been likened to the movements of a riddle as one plays upon it. Crelasimus pugnax is the most abundant species, and ranges from Cape Cod to the Gulf of Mexico. Together with Cambarus it does much damage by burrowing in the levees of the Mississippi River (Fig. 100).
FIG. 105. — Pinnotheres oxtreum. X 4 From Rathbui).
THE CRAYFISH AND ITS ALLIES
111
The economic im- portance of the Deca- poda may be inferred from the fact that the receipts for the lobster alone, taken and sold by United States fishermen, is
Fie, 106. - Gelasimus pugnax. Nat. size. estimated for 1892 Fronto-dorsal view. Photo. l>y W. H. C. P.
at one million dollars. The yield to Canadian fishermen was in ad- dition worth half a million dollars. From the United States Fish Com- mission Bulletin for 1890-91 we find that the bine-crab fisheries on the Atlantic and Gnlf coasts re- turned almost half a million dol- lars, while the shrimp catch in the same waters brought nearly a quarter of a million dollars more. The latter industry on the Cali- fornia coast is much greater, for the shrimp trade of San Francisco Bay alone is valued at a quarter of a million dollars yearly.
The remaining orders of Mala- costraca maybe briefly mentioned. The Stomatopoda1 include only
FIG. 107. — Squt/la empusa, the
Sqililla,2 the mantis shrimp, SO mantis shrimp. Dorsal aspect.
From Bigelow.
1 (rr6/xa, mouth ; TTOUS, foot.
2 <7/d\Aa, classic name for a marine crustacean.
112
ZOOLOGY
called because of a certain resemblance to the mantis insect (Fig. 107). This animal is found on our east coast, where it burrows in the sand. It is a little longer than a crayfish. Being hard to catch, it is not much used as food. The Cumacea include a few small marine Crustacea, not ordinarily seen. They are of interest be- cause of the reduced carapace which is transitional to the condition found in the lower Crustacea. The Isopoda l include
FIG. 108. - - Oiiis'.-us, the sow-bug. Dorsal view. Nat. size. Photo, by \V. H. C. P.
FIG. 10<». - • Talorchestia lonf/ieornis, the beach flea. Nat. size. Photo, by W. H. C. P.
the sow-bugs or wood-lice (Fig- 108), noteworthy for forming the largest group of land Crustacea, and certain marine and fresh-water groups. The Amphipoda2 are exclusively aquatic creatures, found under decaying vegetation on beaches of lakes or the sea (Fig. 109), and crawling amidst marine hydroids. Being laterally com- pressed, the Amphipods tend to lie on one side when at rest.
1 tVos, equal ; TTOVS, foot.
2 d/x0i, both ; Trotfs, foot.
THE CRAYFISH AND IT 8 ALLIES 113
Edible Lobsters. — The American lobster, Homarus Ameri- canus, differs little in appearance from the European lob- ster, If. vulgaris. Formerly the American lobster attained the greater size, but the excessive catches of our species in the last few years are rapidly doing away with this differ- ence. The so-called Norwegian lobster finds its way into European markets, while on our California!! coast the so- called spiny lobster or sea-crayfish takes the place of our true Atlantic lobster, and, like the latter, is said to be in danger of extermination on account of overfishiiief.
c5 O
Edible Crayfish. - The nearest fresh- water ally to the lobster - - the crayfish — has not yet attained the pop- ularity in our markets which it possesses in Europe, particularly in" France. So much is the crayfish esteemed in Paris that the enormous crayfish farms throughout France are unable to supply that city, consequently cray- fishes are imported in considerable quantities from Ger- many. In America, it is our French population mainly that makes a market for the crayfish. Astacus nu/res- cens is the crayfish sold in San Francisco markets. ( )n the Atlantic coast, New York and New Orleans are the main centres of consumption. Cambarus affims, taken from the Potomac River, is the crayfish found in the spring in the New York markets. Later in the season this market is supplied by C. virilis and immunis, which are shipped from Montreal, Milwaukee, and other Western cities.
Edible Crabs. --Of the crabs which reach our market
the most important is the blue crab. These crabs are
kept moored in floating boxes until they have moulted,
and then they are sent to market as soft-shelled crabs.
i
114
ZOOLOGY
The shore crabs, Cancer, are little eaten in the United States.1
Edible Carididae. - The shrimps and prawns have within recent years begun to appear in large numbers in the Eastern markets. For many years the Pacific species
P J? :.*%<s
«*—. -- .M<s^ ^VfcJ* t£v *
£ — ;J£-t3&tral
£• " -* ' / *".. > X" : A A^ ^ .«£
\,:: lawv-
FIG. 110. — Lhniihts 2)o!i/i>Ji"iiiux, the king-crab or horseshoe-crab.
have been dried and shipped by the Chinese in large quantities to China.
1 Very unfortunate is the destruction of the "king-crab," Limulus, which is only distantly related to the Decapoda. In Delaware Bay they are caught in great numbers and ground up as fertilizer. As they are taken only during the breeding season, they are being rapidly extermi- nated. The American Limulus belongs to an order entirely unrepresented 011 the European coast (Fig. 110).
THE CRAYFISH AND ITS ALLIED
115
Development of Lobsters. — Lobsters lay eggs in July and August. In the fall they migrate to deep water, and pass the winter there. In the spring they migrate back to the shore — the females tarrying behind the males until the eggs of last summer, which she still carries attached to her swimmerets, shall be further advanced. In June the young hatch out, moult, and swim to the surface. The
FIG. 111. — An early stage of develop- ment of egg. Appendages becom- ing bifid. Paired dotted areas above indicate eyes ; these are fol- lowed by the first three paired ap- pendages : aiitennules, antennae, and mandibles. Below in the mid- dle line is the forming tail; above is the mouth. After Herrick.
FIG. 112. - - Surface view of egg nauphius. Antennae show begin- ning of segmentation; mandibles and maxillae seen on each side of the abdomen. Embryo 10-18 days old. X 25. From Herrick.
female now moults, 1m t does not spawn again for a whole year ; that is, she spawns in alternate years. The number of eggs carried varies with the age of the female ; middle- aged lobsters may carry up to one hundred thousand eggs, but the old or young ones as few as three thousand. The egg as freshly laid is about 1.5 millimetres in diameter and is stored with food material, called yolk, much as in the case of the hen's egg. As in the chick, the development
116
ZOOLOGY
takes place, as it were, on top of the egg (Figs. Ill, 112). Eyes and mouth appendages early make their appearance; then the other appendages, and the tail (Fig. 113). For a long time the back of the thorax is greatly distended by the yolk stored there, and the eyes are huge (Fig. 114).
Immediately after hatching, the young lobster is about one-third of an inch long. The eyes are still abnormally large, the telson is spatulate, and the abdomen is without
FIG. 113. — Surface view of embryo FIG. 111. — Lobster embryo. 01 days with all of thoracic appendages old ; eyes have developed pigment,
formed. The forked telson partly X 15. From Herrick.
overlies the brain. Note the large eyes, which are yet without pig- ment. Embryo about 21 days old. X 25. From Herrick.
swimmerets. On account of its resemblance to the Schizop- oda, the larva at this stage is known as the " Schizopod larva' (Fig. 115). In moulting for the fourth time, the exopods are lost from the future walking appendages, and the animal resembles a lobster except for its small size (Fig. 115a). During these early moultings the young lobsters undergo a terrible mortality, so that out of ten thousand embryos hardly two, on the average, survive. After the
THE CRAYFISH AND ITS ALLIES
117
fifth or sixth moult the little lobsters sink to the bottom, and then begin their journey shoreward. From this time until they are about four inches long, only very few indi- viduals have ever been seen. This is due, it is said, to the fact that they hide deep down among the rocks, where they cannot be dredged. When they are four inches long or so, they become bolder, leave the rocks, and, like the
FIG. 115. — Larval view of lobster, extracted from an egg which was about ready to hatch. The concretions in the intestine are destined to go into the newcuticula after moulting, x 25. From Herrick.
adults, make burrows for themselves in the sand or under stones.
Development of Crayfish. — The crayfish develops simi- larly to the lobster, — from a large egg filled with yolk. The early stages are much like those of the lobster ; but those changes which in the lobster take place during the first three stages of free life are in the crayfish passed in the egg. Consequently at the time the crayfish hatches it
118
ZOOLOGY
is almost, but not exactly, like an adult crayfish except in size. The telson of the just-hatched crayfish has, to be precise, a somewhat more oval form, and the first pair of swimmerets are undeveloped; but these differences soon disappear.
FiG.lloa. — Third larval stage, lateral view. Note the dif- ference between this and the adult. X 11. From Herrick.
Regeneration of Lost Parts. - -If you attempt to pick up a crab by one of its claws, you frequently find yourself in possession of a portion of the leg only, while the crustacean has made good its escape. Moreover, it will be seen that the leg always separates at a certain place ; namel}r, be- tween the second and third segments. This is the place where a fusion occurs between two segments which are free
TIIE CRAYFISH AND ITS ALLIES 119
in the first larval stage. This power of defensive mutila- tion occurs in those appendages which are most apt to be seized, — namely, the five thoracic legs, — and is wholly under the control of the reflex nervous system, for it may occur when the entire voluntary nervous system has been removed. The leg of a dead crustacean shows no such capacity. If the leg of a lobster is cut off at some point distal to that of normal rupture, the limb will later be found cast off up to this point. Here a sort of double membrane or diaphragm exists, with a central opening only large enough to admit the passage of nerves and blood-vessels. Upon rupture this passage is soon plugged up by coagulated blood — • clearly a device to prevent ex- cessive hemorrhages. Soon after a leg is cut off a papilla- like body grows out from the stump of the limb, develops into the shape of a small limb, and grows larger, with each successive moult, until the normal size is reached. The antennse, too, are much exposed to injury, but with them autotomy is not practised. The}^ begin to grow out at the place of injury, and at least one moult is necessary for their complete restoration.
Abnormalities in the claws of the lobster are not un- common. The thumb-like protuberances of the next to the last of the joints of the great claw is sometimes bifid, or carries a large wart. The finger which opposes the thumb is also sometimes forked (Fig. 116). Many of these abnormalities are probably due to injury of the claw; but others cannot be explained in this way. For instance, cases have been observed of lobsters having crushing claws of equal size on the two sides of the body. An antenna has been seen replacing an eye, and this result may be obtained by cutting off an eyestalk near its base
120
ZOOLOGY
when an antenna will regenerate (Fig. 117), one or two extra oviducts may occur, or double monsters — sort of
Siamese twins - - may be hatched out. Similar monstrosities are found in other arthropods.
Physiological Division of Labor. The difference between a " highly developed " animal and a lowly organized one is not first of all a difference of size nor a difference in the number of parts, - just as a large population or numerous cities are not the pri- mary characteristics of a highly civilized state. But just as a complex civilization is one in which each of the different citizens has his own special task to per- form for the commonwealth, so a highly developed organism is one in which each different o reran
o
has its special role to play. The worm Nereis has more segments
o
to the body than the crayfish, but these segments are very nearly alike — the parapodia especially
FIG. lib. — Two abnormal claws. J
Upper figure shows a double are quite similar. In the crayfish,
CrCe°ther^TextS °" the other hand, the append- finger. From Herrk-k. ages are dissimilar. Each pair
has a special function to perform
and is specially adapted, often complexly fashioned, to meet this need. What is true of the appendages is like-
777 K CRAYFISH AND ITS ALLIES
121
wise true, to an equal degree, of the internal organs. The internal organs of Nereis are repeated in each segment; but in the crayfish the egg-ducts lie in one segment, the heart in another part of the body, and so on. Some of the seg- ments have given up one or more functions to perfect a
Fiu. 117. — Eyestalks of a Decapod dissected out. Oil the right an antenna has regenerated in place of the amputated eye. opt., optic nerve. After Herbst.
single one in which it lias specialized. There has been a division of labor between the different parts of the body, and in consequence a greater perfection in the performance of each function. More perfect fulfilment of function is the result of physiological division of labor, just as a higher civilization is the result of individual division of labor.
122
ZOOLOGY
APPENDIX TO CHAPTER YII
KEY TO THE SIX CHIEF ORDERS OF MALACOSTRACA
Body segments, 20 ; abdomen with 7 segments ;
at least 1 pair of maxillipeds. 61. Cephalothorax with carapace, at least 2 pairs
of maxillipeds [Thoracostraca]. Ci. Eyes stalked.
d\. No uncovered thoracic segments ; 3 or 2 pairs of maxillipeds, and 5 or 6 pairs of legs ....
<72. 3 free thoracic segments ; 5 pairs of
maxillipeds ; 3 pairs of legs c2. Eyes not stalked ; 4 to 5 thoracic seg- ments not covered by carapace ; 2 pairs of maxillipeds ; 6 pairs of thoracic legs b'2- Cephalothorax without marked carapace ; usually 7 free thoracic segments ; only 1 pair of maxillipeds ; eyes not stalked [Arthrostraca].
d. Body usually broad ; abdomen with short, often-fused segments, and with gills
on legs
c2. Body laterally compressed ; abdomen mostly elongated, with 3 pairs of swim- ming legs, and behind them 3 pairs of springing legs ..... «o. Body segments, 21, enclosed in bilobed shell, abdomen with 8 segments ; the last 2 without appendages ; no maxillipeds [Leptostraca]
Podopthalmata
(Ex. Crayfish)
Stomatopoda
o
Cnmacea
Isopoda
Amphipoda
Neb ali <v
The crayfish belongs to the order Podopthalmata. The following is a key to the most important families of this order : —
«i. 3 pairs of maxillipeds which differ in form from the following 5 pairs of thoracic legs ; the latter are locomotor, and often end in pincers [sub- order Decapocla].
APPENDIX TO CHAPTER VII 123
Body mostly depressed ; antennae short ; abdomen short and folded under the cepha- lothorax, with 1 to 4 pairs of appendages, and usually without tail-fin [superfamily Brachyura].
Ci. Male duct opens on thoracic plate ; ce- phalothorax usually quadrangular, at times transversely oval; anterior lateral area (liver area) of carapace small ; usually fewer than 9 pairs of gills; orbits look forward or obliquely downward . Catometopa
(Square Crabs; Fiddler-crabs) C2. Female opening on broad thoracic plate ; male opening on coxa of 5th pair of thoracic legs ; 9 pairs of gills. d]_. Cephalothorax broad, diminished be- hind, bowed in front ; liver area large ; orbits directed obliquely up- ward and forward .... Cyclometopa
(Arched Crabs) dz- Cephalothorax triangular, anteriorly
pointed, with longer or shorter ros-
V
trum ; liver area small ; orbits di- rected outward .... Oxyrhyncha
(Triangular Crabs ; Spider-crabs) Body mostly elongated ; antennae long ; ab- domen long, not bent under, or only partly so, typically with 5 pairs of legs and a large tail-fin [superfamily Macrura]. c\. Last pair of thoracic legs shoved back- ward and rudimentary. d\. Last thoracic segment not free ; ab- domen with hard shell, hinder half turned under ; first pair of legs typically non-chelate . . . Hippidce
(Mole-crabs) c?2- Last thoracic segment free ; abdomen
typically with thin cuticula, un- symmetrical and with rudimentary legs ; first pair of legs very large, chelse unsyrnrnetrical , . Paguridce
(Hermit-crabs)
124
ZOOLOGY
C2. Last pair of thoracic legs not shoved
backward.
6?i. Antennae without squame ; first pair of thoracic legs chelate ; cephalo- thorax with 2 longitudinal lines . d%. Anteniue with squame.
e\. ISquame small ; antennules and antennas near each other ; first pair of thoracic legs very heavy with great chelae ; cephalo- thorax with cross-suture ; gills brush-like
6>2. Squarne large ; antennas usually under antennules ; first pair of thoracic legs with small chehe ; cephalothorax without cross-suture, gills laminate
ThalassimdcB
Astacidcb
(Ex. Craylish)
C arid idee
(Shrimps and Prawns)
n-2. 2 pairs of maxillipeds resembling the 6 following pairs in being bifid [suborder Schizopoda].
CHAPTER VIII
THE DAPHNIA AND ITS ALLIES
Relationships. — Daplmia1 belongs to the division of Crustacea called Entomostraca.2 The Entomostraca 3 are distinguished from the higher Crustacea — the Malacos-
O <— '
traca - -by the negative character that the number of segments and appendages in the body is variable, instead of there being constantly 10 pairs of appendages.
The group of Entomostraca to which Daphnia belongs comprises the more primitive of living Crustacea. They occur in both fresh and salt water and, excepting Protozoa, are the most abundant aquatic animals. They are of great economic importance, since they constitute the main food supply "of fish. On the coast of Norway and Scotland the fishermen prepare for a catch of herring or mackerel when the sea becomes red with Entomostraca. Whalers like- wise seek their booty where these Crustacea are abundant on the open seas, for even the whalebone whales devour the small animals in great quantity, straining them out of the sea-water by means of their whalebone strainers. De- spite all their enemies, the numbers of Entomostraca are maintained by virtue of an enormous fertility. The
1 From Aa0i/77, daughter of the river-god Peneus ; she was transformed into a laurel tree.
- efTo.i'.oi', cut into, segmented ; oarpaKov, shell.
3 The live orders of Kntomostrara may be distinguished by means of the key given at the end of this Chapter, page 131.
125
126 ZOOLOGY
Entomostraca are rich in species also, partly because they occur in such diverse environments. Thus they live in fresh water, in the sea, and even in the Great Salt Lake and in vats where salt is crystallized out. They live in little pools, such as dry up in summer. They are found also as parasites on the gills or in the skin of fishes.
Habitat and Food. - - Daphnia 1 lives in ponds, lakes, and slow-running streams over all the globe. During the fall in northern latitudes the Daphnias, of at least certain species, lay fertilized eggs, called winter eggs, which may lie dormant, however, not merely for the winter but throughout an entire year. During most of the year females alone occur and unfertilized "summer eggs" are alone produced.
The abundance of Daphnia in any pond is determined by a number of causes. One of the most important of these is food. The food of Daphnia consists chiefly of fresh-water algre, such as nostocs and diatoms ; and it has been shown that the abundance of Daphnia in a pond is closely determined by the abundance of the kind of alga
1 Key to the principal genera of the family Daphnidse : —
a i. Head rounded, not beaked.
&i. Antennules long ; abdomen not wholly cov- ered by shell Moina
b-2. Antennules short ; whole body enclosed in
shell Ceriodaphnia
a-2- Head beaked below.
bi. Beak slight ; shell angled below or extending in long spines from lower angle ; pigment spot roundish Scapholeberis
ft2. Shell rounded below, with a blunt spine above ;
pigment spot elongate .... Simocephalus
63. Shell extending in sharp spine at upper pos- terior angle ; pigment spot small . . Daphnia
THE DAPHNIA AND ITS ALLIES
127
ant.i ant.Z
abd.f
which forms its principal food. Another factor upon which the number of Daphnia in a pond depends is tem- perature. A high temperature seems to be unfavorable to Daphnia, so that not the summer, but the spring and autumn are its periods of maximum reproductive activ- ity. This activity is like- wise checked in winter even though there is plenty of food.
The family Branchiopoda 1 is closely allied to the Clado- cera. The common repre- sentative of this family, Branchipus, has an elongated, distinctly segmented body whicli carries eleven pairs of lobed, leaf-like feet, func- tioning both as respiratory and locomotor organs. Like
Daphnia, Branchipus pro-
- • FIG. 118.--Apus glacialis, ventral
dlices Winter eggs Which Can aspect, abd.f., abdominal feet;
Withstand desiccation even «nt' f > antennule ; ant. 2, antenna ;
lor., labrum ; ma., mandible ; mx., for years ; indeed, in Some
cases, a certain amount of desiccation is a prerequisite of hatching. Apus differs from Branchipus in having a broad shield (Fig. 118). The family Ostracoda2 comprises some very abundant,
1 j3pdyxia-> gills ; Totfs, foot.
2 HxrrpaKov, shell of a testacean ; eI5os, like.
first maxilla; ov., aperture of ovi- duct: .s. /. pi., sub-frontal plate; •s7f. f/l., shell-gland; tli.f., thoracic feet; th.f. 1, first thoracic foot. After Bernard.
128
ZOOLOGY
minute, bean -shaped little crustaceans, which have to move their appendages very vigorously to support their heavy bodies in the water. The Ostracods are found in almost all pools and streams,, especially in the early spring. Many of them seem to be exclusively parthenogenetic.
/
V
FIG. 119. — Acartia, a marine Copopod. Greatly magnified. Photo, by
W. H. C. P.
Of the Copepoda1 the commonest fresh-water genus is Cyclops, which occurs in a similar habitat witli Daphnia and is sometimes found even in pure drinking water. The female carries a conspicuous egg-sac on each side of the abdomen, and reproduction occurs with such rapidity that
oar ; Trews, foot.
THE DAPJfNTA AND TTS ALL1KS
129
one Cyclops might, under the most favorable conditions, have 5,000,000,000 descendants in one year. It is conse- quently easy to understand how Cyclops often becomes the most abundant eiitomostracan in our waters, and how in some lakes it has been found that there are over one million of them to each square metre of water surface. Large numbers of the Copepoda are marine. One of the most common is Acartia (Fig. 119), which swarms to such
FIG. 120. — Mussel-shell bearing barnacles (Balauus). Photo, by W. H. C. P.
an extent on the surface of the water as to make great phosphorescent areas.
Barnacles are the only attached non-parasitic Crustacea. Certain species of them are found fastened to rocks on the seashore at low-tide mark. If you watch barnacles in rock pools, you can see them open the valves of their shells, protrude their elongated appendages, which together form a sort of rake, and pull in particles which happen to be float- ing about them. Other species of barnacles attach them- selves to floating seaweed, ship bottoms, and whales ; under these circumstances, despite their sessile habit, they enjoy a constant change of locality. Barnacles doubtless gain great protection from the circumstance that they are
K
130
ZOOLOGY
sessile and enclosed in shells ; but their peculiar habits have given rise to certain peculiarities in reproduction. They are hermaphroditic; i.e. both male and female germ- cells occur in the same individual. Despite this fact, dwarf male individuals are occasionally found inside the shell of the barnacle ; these are known as " complemental males." The general form of the barnacles has also be-
come greatly modified by their sessile habit, so that they were long regarded as mol- lusks, until it was shown that the larvje are almost exactly
i/
like those of other Ento- mostraca.
Trilobites1 are extinct giant Entomostraca, closely allied to Branchipus. They were immensely abundant in early geologic times, and their re- mains form a large part of certain rocks. They had a segmented body, with bifid appendages and long antemue,
T ,1 T
- 101 . , ,. and their compound eyes were
FIG. 121. — A restoration of the J
borne on the great frontal ""eld. Some of them were Beecher. nearly half a metre long.
ventral aspect of a Triiobite.
1 Having three lobes.
APPENDIX TO CHAPTER VIII 131
APPENDIX TO CHAPTER VIII
KEY TO THE FIVE ORDERS OF ENTOMOSTR A.CA
a\. Free-living or parasitic inhabitants of the sea or
of fresh water. ?>i. 2 pairs of maxillae.
t'i Mandible without palp ; 4 or more pairs of foliate swimming legs behind maxillae [Phyllopoda]. di. With 10 to 40 pairs of legs . . Sranchiopoda
(Ex. Branchipus)
(Z2. With 4 to 6 pairs of legs . . . Cladocera
(Ex. Daphnia)
Co. Mandible with leg-like palp ; only 2 pairs
of appendages behind maxillae . . Oatramiltt
60. Only 1 pair of maxillae, followed by 4-5 pairs
of bifid, oar-like feet ; often deformed as a
result of parasitism Copepnda
(Water-fleas)
«o. Sessile marine animals, whose body is surrounded by a usually calcified mantle ; 6 pairs of tendril- like feet Cirripedia
(Barnacles)
Key to the principal families of Cladocera, to which group Daphnia belongs : —
a\. Body enclosed in a bivalve shell ; mandibles trun- cate below ; maxillae distinct, spiny.
61. 6 pairs of similar, foliaceous, distinctly
branchiate feet ; swimming antennae with 2 unequal ranii ; intestine straight . . SididcK
b-2. 5 (or 6) pairs of feet, the anterior pair more or less prehensile and destitute of branchiae. Ci- Ranii of antennae 3- and 4-jointed ; 5 pairs of feet, the last with a curved appendage guarding the branchial sac ; antennules of the female sort, 1 -jointed Daph nidus
132
ZOOLOGY
Co. 0 pairs of feet ; an ten miles elongated,
many-jointed . . . .
Cg. Antennae with both ranii o-jointed ; in-
testine convolute .....
Body wholly or nearly destitute of a bivalve shell ;
feet not branchiate, spiny ; abdomen curved,
ending in two long stylets
Bosminidce Lynceuhe
Polyphemidce
CHAPTER IX
THE EARTHWORM AND ITS ALLIES
Relationships.- -Earthworms1 belong to an order of Annelids known as Oligocheeta.2 This group is distin- guished by a prevailingly non-marine life, by the absence of parapodia, by few bristles, and by the absence of tenta- cles, palps, cirri, and gills.3
Habits. — Earthworms, as the name implies, are inhabit- ants of the ground, through which they burrow and in
FIG. 122. — Flash-light photograph of earthworm and slug crawling on a pave- ment at night. Photo, by D. and S.
1 There are not very many kinds of terrestrial Oligochseta. The prin- cipal American species may be distinguished with the aid of the key given in the Appendix to this Chapter.
- 6X1705, few ; XCU'TT?, hair.
3 The Oligochfeta exhibit two principal subdivisions ; the first of which includes terrestrial species of the single family Lumbricidse, and the second various aquatic families, — a key to which is given on page 144,
] 33
134 ZOOLOGY
which they gain their food. They sometimes come to the surface at night in search of companions and food (Fig. 122). Even during the day in rainy weather they extend the anterior end of the body out of their burrows. Earth- worms, found on the surface at other times, have, for the most part, been parasitized by a fly, and are in consequence weak or dying. During the daytime, if the surface mois- ture permits, they lie near the mouth of their burrows, probably for the sake of the sun's warmth. In this posi- tion they can be seen by looking down into the holes. At such times they are often caught by birds. In dry weather, or when the ground is freezing, earthworms burrow deep to a moist stratum, or to below the frost line, and hiber- nate there.
Food. — EartliAvorms are omnivorous. As they burrow through the ground, the earth is taken into the alimentary tract, and the digestible particles are dissolved out and absorbed as food. Earthworms can, however, be fed upon green and dead leaves, decajdng wood, seedlings, bits of flesh, and even filter paper. Earthworms have the habit of dragging into their burrows leaves which they intend to devour. There the leaves are moistened with a fluid excreted by the worm. This fluid partially digests the food. After being taken into the alimentary tract, the food reaches an organ of the canal known as the gizzard. This part has thick muscular walls, and contains in its cavity small stones ; by the action of both the muscular gizzard and the small stones, the food is ground up in much the same way as are the grains of corn by the aid of stones in the gizzard of a hen.
Resistance and Regeneration. - -The capacity which earth- worms possess of resisting certain untoward conditions is
THE EARTHWORM ANT) ITS ALLIES 135
very great. Thus they may be kept for months in a moist vessel without food, or with only filter paper, with- out starving. On the other hand, they die in a dry atmos- phere in a few hours, whereas they may be submerged in water for several days without injury. Very remarkable is their power of healing after injury. If an earthworm be cut in two near the middle, and the halves be kept under favorable conditions, each half may develop its missing organs so that two complete worms will result. The anterior half of one worm may be attached to the hinder end of a second worm by the cut edges, owing to the fact that the cut edges grow together. This operation is called grafting.
Economics. - - Earthworms are, to a certain extent, in- jurious to vegetation, since they eat tender seedlings and roots, but, on the other hand, they are almost indispensable to agriculture. Their burrows permit rain to percolate deep into the ground, instead of running off on the sur- face. They keep the soil loose, facilitating the penetration of the roots of plants. The earth that passes through their bodies is ejected on the surface of the ground near the openings of their burrows, and is called a " casting." By means of castings the deeper-lying earth is brought to the surface, and the surface layer of rich earth, called " vegetable mould,'1 is in this way increased in thickness by additions to its upper surface. The thickness of the layer of mould which the castings of one year, if uniformly spread out, would make has been estimated by Darwin to be in England about two-tenths of an inch. Most of these castings are merely taken from the deeper-lying mould, but they are enriched by the intestinal secretions in pass- ing through the body of the worm. These intestinal secre-
136 ZOOLOGY
tions are said to have the power of slowly dissolving sand and thus of turning it into soiL Darwin says, " It is a marvellous reflection that the whole of the superficial mould over any smooth expanse has passed, and will again pass, every few years, through the bodies of worms. The plough is one of the most ancient and most valuable of man's inventions, but long before he existed the land was, in fact, regularly ploughed, and still continues to be thus ploughed, by earthworms."
The group to which earthworms belong is closely related to that which includes Nereis of the seashore. They are both ringed worms or Annelids.1 But whereas Nereis and
O
its allies have parapodia provided with numerous bristles, the earthworm has 110 parapodia, and only a few bristles on each segment. The group to which Nereis and its allies belong is called (see Chapter X) Polychseta, and the group to which the earthworm belongs is appropriately named Oligocliceta.
The aquatic Oligochaeta2 are among the commonest inhabitants of ponds and ditches, living sometimes in the mud and sometimes at the surface of the water.
Tubifex3 is common in slow-running brooks, and lives in the mud of the bottom, forming tubes in it. The thread-like bodies of the worm are stretched up beyond the surface of the mud and wave in the water in graceful undulations. Often the worms are so numerous that their reddish color gives a decided tinge to the bottom. They thrive well in fresh- water aquaria.
1 Annulus, a little ring.
2 A key for the determination of the principal families of aquatic Oligo- chseta is given in the Appendix to this Chapter, page 144.
3 tubus, tube ; face re, to make.
THE EARTHWORM AND ITS ALLIED
137
Dero 1 is very common on the surface of ponds, particu- larly in the midst of duck-weed (Lemna), the leaves of which it cements together to form a floating tube in which it lives, and by which it is accompanied in all its migra-
Fm. 12o. — Dero, the duck-weed worm. Enlarged. After Reighard. The lettering is as follows : or., mouth ; phx., pharynx ; oe., oesophagus; ftff. <>., segmental organ ; in., intestine; pav., pavilion or tunnel; dg. app., finger- like appendages. From Reighard.
tions. Dero can also be told by the sort of funnel at the hinder end of the transparent body, from the margins of which finger-like filaments arise which aid in respiration (Fig. 123).
Nais2 does not construct tubes, and it has no respiratory
, to skin (= flay).
2 PCUS, a water-nymph.
138
ZOOLOGY
filament at the hinder end of the body (Fig. 124). It also
has eyes ; while Dero has none. Both Dero and Nais have
the interesting habit of reproducing by dividing the body transversely. In the middle of the body tentacles begin to arise, a new mouth is formed, and the worm constricts into two. I n d e e d, sometimes several new heads may be forming in the midst of a single worm. This habit is of advantage not only in multiplying the number of individuals of the species, but also
as a means of protection. For if, by chance, the larva of
the water-beetle Dytiscus seizes a Nais
and bites it in two, the part which escapes
can go on developing new^ individuals. The slow-moving, burrowing habit of
the earthworm has led to a nearly complete
absence of such appendages as Nereis
possesses. There are other ringed worms
i • T , i i . i -i •, FIG. 125. — Phasci)-
in which the burrowing habits have led to iosoma, a Gephy-
a loss even of the segments in the adult. rean- One-fourth
r™ • • , i ,-, ,. nat. size. From
11 us is the case in the group Gephyrea.1 Leunis.
1 ytfivpa, bridge ; because they were once considered to bridge the gap between holothurians and worms.
FIG. 124. — Nais: a, mouth; b, anus; c, intes- tine. From Leunis.
THE EARTHWORM AND ITS ALLIES
139
This group contains several rather rare animals. One
of the commonest is Phascolosoma,1 which is a tough but
smooth-skinned, cigar-shaped worm, which one can dig up
on our sandy beaches (Fig. 125). One end is pointed ;
from the other a great proboscis
terminating in tentacles surround-
ing a mouth can be extruded.
Another species found on our
beaches after a storm, something
like a small cucumber in shape and
size, has a row of bristles at each
end, indicating its relationship
with the bristle-bearing worms.
This species, Echiurus,2 is seg-
mented when young like Nereis,
but eventually it loses its seg-
mentation (Fig. 12(>). Several
species of Sipimculus are edible,
and are held in esteem by the
Chinese.
To the account of the Oli- gochreta above given may be
postset
added some statements concern- Fm'
one-half nat. size.
About prob.,
proboscis ; ant. set., anterior seta;; post, set., posterior setjB. After Greef, from Par- ker and Haswell's " Text- book."
ing a group of annelids of very different appearance. The leeches, or " blood-suckers," are flattened Avorms, Avhich, like the earthworm, show metamerism ; that is, there is a repetition of the in- ternal organs. They are also segmented ; that is, the body 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 e'x<s> 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 at the posterior end of the body for the purpose of adhesion (Fig. 127). They usually have a smaller, anterior sucking disk around the mouth, which may or may not be provided Avith 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
FIG. 127. — Clepsine, the flat blood-sucker. Ventral view. Posterior sucker at left. Nat. size. From life. Photo, by E. R. D.
live in water ; but in Ceylon there is a land leech which lives in foliage and attacks man and other animals. ( Hlier leeches may live in damp places at a considerable distance from water. Leeches suck the blood of fishes and other aquatic animals. Certain kinds devour worms, insects, and other small creatures.
The commonest of the larger blood-suckers of our waters is Nephelis,1 which is not distinctly segmented. It" varies from black to slate color, and is sometimes striped or spotted. 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 is common under floating wood. It feeds on snails and creeps like the inch -worm. The female carries its young attached to its under surface (Fig. 127).
FIG. 128. — Pedicellina americana, an encloproctous bryozoan. A colony, magnified 15 diams. Photo- of living animals by W. H. C. P.
Possibly allied to the Gephyrea is the group of Bryozoa,2 or moss-animals. These are noteworthy from the fact that they are compound, many individuals budding off from one another, as in plants. They are found abundantly both in the sea and in fresh water. Two main groups are dis-
1 From K-XeVTw, to steal. 2 fipvov. moss ; faov, animal.
FIG. 129. — Buyula turrita, a marine ectoproct. A colony, magnified 1.5 diams. Photo, of living animals by W. H. C. P.
FIG. l.'it'. — PlumateUa polymorpha, a fresh-water ectoproct, magnified 1.5 diams. Photo, of living animal by W. H. C. P.
142
APPENDIX TO CHAPTER IX
14°
o
tiiiguislied, the Endoprocta (Fig. 128), in which the individual consists of a long stalk and a " head ' or body proper ; and the Ectoprocta (Figs. 129-131), usually without such a stalk. The Ectoprocta are the prevailing type. The marine species form lace-like mats on sea- weed or stand up as branching, bushy colonies (Fig. 129). Some of the fresh-water forms make loose, antler- like colonies (Fig. 130), while others lie on the surface of a more or less spherical mass of jelly which they have themselves secreted (Fig. 131).
FIG. -131. -- Pectinatella maf/nijica,a, dense complex of colonies, growing upon a stick. Each star-shaped group represents a single colony. One-half uat. size. Photo, of living mass by W. H. C. P.
APPENDIX TO CHAPTER IX
KEY TO THE PRINCIPAL SPECIES OF EARTHWORMS OF THE
UNITED STATES
ffi. Clitellum begins on segment xiii or xiv ; $ pore on segment xviii or xix ; 2 gizzards in segments v and vi.
61. 2 dorsal vessels ; lives in soil of prairies
62- 1 dorsal vessel ; lives in river-bottom land Clitellum does not begin in front of segment xviii ; $ pore on segments xii and xiii, or (usually) xv. 61. Prostomium incompletely divides buccal lobe [genus Allolobophora],
( Diplocardia \ commit nis D. riparia
144 ZOOLOGY
ci. Tubercles on segments xxviii-xxxi ; ill- smelling ; purple-banded ... A. fcetida
Co. Tubercles on segments, xxxi and xxxiii . A. caliyosa
r3. Tubercles 011 segments xxvii, xxviii ;
color reddish brown .... A. tumid a
r4. Tubercles on segments xxiv-xxx ; about
100 segments ..... A. parva
05. Tubercles on segments xxviii-xxx . A. subrubicunda
c$. Tubercles on segments xxix-xxxi (occa- sionally xxix, xxx); number of seg- ments, 150 A. rose a
62- Prostomium completely divides buccal lobe [genus Lumbricus] .
Ci. Tubercles on segments xxviii-xxxi ; red- brown or purple ; about 120 segments. L. ntbellus
Co. Tubercles on segments xxxiii-xxxvi ;
number of segments, 180 L. hercnleus
KEY TO THE PRINCIPAL FAMILIES OF AQUATIC OLIGOCH^ETA
a\. Dorsal blood-vessels visible only in the anterior part of the body ; farther back, as intestinal sinus, disappearing underneath the intestinal
glands EnchytneMas
rto. Dorsal blood-vessels running on top of food canal
and visible throughout its entire length. &i. In each segment, except the first, contractile
lateral blood-vessels Lumbriculidas
bo. Lateral vessels contractile only in anterior
segments.
Ci. Dorsal and ventral vessels united in each segment, except in the first 5, by 2 lateral vessels Tubificidce
(Ex. Tubifex)
Co. Dorsal and ventral vessels united in each
segment by a lateral vessel . . . Naidce
(Exs. Nais, Dero)
CHAPTER X
,-*
NEREIS AND ITS ALLIES
NEREIS1 is one of the commonest worms found on our seacoast. It occurs in sandy or muddy beaches, at or below low-water mark, especially where tidal currents flow swiftly. It inhabits burrows, which it makes in the sand and lines with a mucilaginous secretion to bind together the walls of sand or mud. At certain seasons of the year, during the breeding season, these worms may be found swimming near the surface of the sea.
Nereis lives on both plant and animal food. To capture its prey it thrusts out a long proboscis, provided with two powerful jaws. The thrusting out consists essentially of a rolling inside out, — just as the finger of a glove may be rolled inside out. When the proboscis is rolled in again, the jaws, retaining their grip on the food, carry it into the food canal. While many kinds of small animals serve Nereis as food, it is itself devoured by various fishes which dig it out of the sand or capture it when it swims free at night or during the breeding season. Such a favorite with fishes naturally makes excellent bait, and is well known to fishermen under the name " clam-worm " or "sand-worm."
Nereis is distinguished by the fact that its segments are numerous and nearly all alike, and bear appendages of similar form. The single pair of jaws on the proboscis is
ts, daughter of Nereus, one of the Nereids, or sea-nymphs. L 145
146 ZOOLOGY
characteristic ; and the four eyes on top of the head, com- bined with two antennae and two palps, serve to determine its family with precision. The parapodia have a dorsal and a ventral cirrus. The commonest species on the coast of New England and in Long Island Sound is Nereis virens,1 which grows to a length of thirty centimetres. Its color is dull green to bluish green, and iridescent. The gills on the parapodia are green at the head end, but farther back they become bright red, owing to the blood which flows through them. This species lives in northern seas, and is found on the coasts of Great Britain, Norway, Labrador, and south
FIG. 132. — Euglycera. One-half natural size. Photo, by W. H. C. P.
to Long Island Sound. South of Long Island Sound the commonest species is Nereis limbata? which grows to a length of, at most, only fifteen centimetres, and is of a dull brown or bronze color. This species is found as far south as South Carolina.
Often associated with Nereis in sandy beaches is a large, strong, flesh-colored worm, pointed at both ends, so that the head is not nearly as evident as in Nereis, and having small appendages, so that it looks smooth like an earthworm. This
1 Green. 2 Bordered or edged.
NEllEIfi AND TT8 ALLIES
147
is Euglycera.1 Its proboscis has four jaws, situated at the corners of a square, instead of two as in Nereis. The pointed head and powerful writhing muscles enable the animal to burrow with great rapidity (Fig. 132).
A second kind, Autolytus,2 is a small animal which lives in little tubes attached to algre or hydroids (Fig. 133). The parapodia at the anterior half of the animal are different from those at the posterior half, for the latter are large and fitted for swim- ming. Eventually one of the middle segments of the body becomes trans- formed into a head, with eyes and tentacles, then the whole of the hinder half breaks off spontaneously. The newly formed head is now the head end of the new individual. This individual leads a different kind of life from the half which remains in the tube, for it swims freely in the water. The separated individuals are either male or female, whereas the part which lives in the tube never pro- FIG 133. -1 Autolytus duces eggs, but merely forms a new tail every time the old tail is cut off to form a sexual individual.
A third kind, Lepidonotus 3 is characterized by the possession of
a
representative of a fam- ily of Polychreta in which the animal bin Is off male or female in- dividuals from its hinder end. bud, head of the budded individual. After A. Aijassiz.
1 e5, typical ; rAikepa, a woman's name, also applied to a family of Polychseta. Euglycera means typical of the family GlyceridaB.
2 auros, self ; AIAJ, to separate ; hence, self-separating.
s, scale ; ^WTOJ, back.
148
ZOOLOGY
a double row of scales covering over the back (Fig. 134). These scales are outgrowths of the dorsal part of the parapodia, and serve for respiration. In allied genera the scales are covered with bristles, which may be so very long and abundant as to hide the scales. They produce a brilliant iridescence. One of these worms with the great bristles may be several inches long and relatively broad, and is commonly known as the "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 deep water, - - so that they are not com- monly seen at the seashore.
The sedentary Polychaeta are mostly smaller and less familiar animals than the free-living Polychseta, but they have an interest for us in showing how greatly modified an organism becomes when it takes on a sedentary life. Its swimming appendages become rudimen- tary ; its eyes are usually lack- ing ; there is no protrusible proboscis armed with powerful jaws ; the gills become grouped almost exclusively about the
FIG. iai.— Lep- idonotus, the scaled 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 at the bottom of a funnel, which receives as food small parti- cles floating in the water ; even the segmentation of the body becomes lost at the hinder end of the animal ; in a word, all those organs which are useful for active carnivo-
o
rous life have become re- duced to the bare needs of a quiet herbivorous life.
FIG. 1 ;>(.). — Amphitrite, removed from its Fi<;. 137. — Polycirrus, the blood tube. Nat. size. Photo, by W. H. C. P. spot. Nat. size. Photo, by
W. H. C. P.
The first of these sedentary worms that we have to con- sider is not completely modified from the type found in free-living species.
Cirratulus 1 lives in tubes in mud or sand. It is yellow
1 From cirrus, curl, ringlet.
150
ZOOLOGY
or orange in color, and has long cirri, which, arising from nearly every segment, reach out in all directions. These function as gills, and when broken off may remain alive for days.
Clymenella,1 which looks like a reddish, jointed straw, builds tubes of agglutinated sand, and has a serrated, funnel- shaped tail end. Its parapodia are very small (Fig. 139).
FIG. 138. — Tube of Cistenides. Nat. size. Photo, by W. H. C. P.
Fid. 139. — Clymenella, straw- worm. The anterior seg- ments only are shown. After M. Lewis.
Amphitrite2 (Fig. 136) builds firm tubes of sand. From the head spring numerous tentacles and three pairs of blood- red gill-tufts. The body is large anteriorly but becomes slender behind, where there are no bristles. Allied to Amphitrite are a large number of common worms found on our coast. Polycirrus, or the blood-spot (Fig. 137), is somewhat smaller than Amphitrite and characterized by a
1 Diminutive of K\vfj.evr}, daughter of Oceanus.
2 ' A.fjuj>tTplTij, wife of Neptune, goddess of the sea.
NEREIS AND ITS ALLIES
151
uniform crimson color and a large number of cirri massed at the head. The tubes made by some of the Terebellidee are very beautiful. The tube of Cistenides (Fig. 138) is found in the sand under stones and is composed of grains of sand cemented together and regularly arranged so as to form a firm wall.
Finally, Serpula1 secretes crooked, round calcareous tubes, which may be found adhering to stones near low water (Fig. 140). From the mouth of the tube the head, with its tentacles, may be protruded, but it quickly re- tracts from danger and closes the open- ing of the tube as a marine snail does its shell, by means of an operculum or lid.
Some worms have gained a parasitic habit, and in con- sequence have become much modified in form and struc- ture. Such is the case with some of the round- worms. Some of these are thread-like, live in springs or pools, and are regarded by the uninitiated as animated horse-hairs. Others are spindle-shaped, as for example the "vinegar eel" and the round- worms that are common in stagnant water. Others live in the food canal, as for example the stomach worm (Ascaris) of the horse and the
1 Diminutive of serpens, serpent.
FIG. 140. — Serpula tube on a bit of oyster shell that is perforated by the boring sponge. The tube lies in the centre of the figure. Nat. size. Photo, by W. H. C. P.
152
ZOOLOGY
B
FIG. 141. — Trichina. A, encysted form in muscle of pork; B, female; (', male; bh, envelope of cyst; cy, cyst; de, male duct; e, embryos; /, fat globules; h, testis ; mf, muscle fibre; oe, pharynx; ov, ovary; no, opening to egg duct; zh, cell masses in intestines. After Clans.
NEREIS AND ITS ALLIES
153
T)
pin-worm of man. Others still penetrate into the mus- cles, and cause great pain and often death. Such is the pork-worm, Trichina,1 which gets into man through un- cooked pork, multiplies in the food canal, migrates in great numbers into the muscles and encysts itself there (Fig. 141). Another group which is largely parasitic is that of the flatworms. Some flatworms live free in ponds. They will be found abundantly among plants taken from small ponds in the summer and autumn, and are commonly known as Pla- naria2 (Fig. 142). They may be recognized not only by their flattened form, but also by a curious proboscis which pro- trudes from the middle of the under side of the body and bears
«/
mouth at its tip. These
a
FIG. 142. — Species of fresh-water Plaiiaria. 1, Dendrocoelum lacteum, cream color; -, Pla- naria maculata ; 3, head end of same to show light streak. After Woodworth.
creatures have a marvellous
power of regeneration, so that
every piece into which a worm
is cut will reproduce an entire
one (Fig. 143). If the worm
is mutilated but not wholly cut in two, bizarre forms may
result by a modified tendency to regenerate (Fig. 144).
Other flatworms are parasitic, such as the liver-fluke of the sheep (Fig. 145). This destructive parasite has a
hair. 2 planus, flat.
154
ZOOLOGY
complicated series of stages to go through before it be- comes adult. Thus the flukes in the liver of the sheep produce eggs which develop into embryos. These em- bryos get out of the liver into the food canal, and thence
-ij:
V
ec.10.
\J
\J ~Mixrch13.Apr.4-. Jan.25. FA.5. Fe~b,17
\
V
§ |
J)&c.10. V
Jan. 2 5.'
FIG. 143. — Showing results of cutting Planarians into two pieces ; the pieces develop into entire animals. After Morgan.
to the exterior. If they are deposited near a pool of water, they may develop further, otherwise they must die. In the water a ciliated larva l hatches from each egg, swims about for a time until it finds a fresh-water snail, bores into it, and encysts itself there. In this
1 Fig. 146, A.
NEREIS AND ITS ALLIES
155
FIG. 144. — Showing abnormal forms resulting from mutilation of Plu- narians. After Van Duyue.
encysted stage the worm is known as a "sporocyst," because it is full of germs (spores) of a new genera- tion.1 The spores develop in the snail into curious organisms, a sort of second-
o
ary larvae known as redia.2 The redise may produce, by a kind of internal budding, new redise, and so on re- peatedly, until at last, on the death of the snail, or from some other cause, the last generation of redia} produces liver- flukes.3 The young liver-flukes wriggle out of the snail, attach them- selves to damp grass, lose their tails, and encyst them- selves. If these cysts be eaten by a sheep, they develop in the sheep's body into an adult liver-fluke (Fig. 145). Thus the stages which we can recognize in the liver-fluke are : -
First generation : egg from liver-fluke, larva,
and adult sporocyst. Second generation : redia (this may be several
times repeated). Third generation : " cercaria " larva, encysted
larva, and adult liver-fluke.
1 Fig. 140, B. 2 Fig. 140, C.
3 These, while young, have tails, and are called " cercaria."
ever
FIG. 145. - Distomum, the liver-fluke. Nat. size. Excr., excretory pore; mo., mouth; rep?'., reproductive aperture ; -srA1/*., posterior sucker. From Parker and Has- well.
156
ZOOLOGY
Another flat worm is such an abject parasite that it has lost most of the organs usually possessed by worms. This is the tapeworm (Fig. 147). When the eggs of the tape- worm are taken into the body of an herbivorous animal, the embryos develop there for a way and then stop. When flesh containing these embryos is eaten by a carnivorous
eye .
(fast.
or.su
c&s
B
FIG. 146. — Development of Distomum. A, ciliated larva ; /?. sporocyst con- taining developing rediae ; C, redia, containing a daughter redia and embryo liver-flukes; D, free-swimming, tailed larva of liver-fluke;- b. op, birth opening; etit, food canal of redia; eye, eyespots ; gast, young redia; r/erni, mor, early stages in formation of the embryo liver-fluke; int, intestine of larval liver-fluke; o?s, oesophagus; or. SK, oral sucker; pap, head papilla of ciliated larva, A: ph, pharynx; proc, processes of redia; vent, su, ventral sucker. After Thomas.
animal, the embryos attach themselves to the food canal of
•>
their host and form, by rapid growth, a long chain of seg- ments, each of which is full of germs. The chain, or
NEREIS AND ITS ALLIES
157
FIG. 147.— Tsenia solium, the human tapeworm. Entire specimen, about natural size. Cap, head. After Leuckart.
158
ZOOLOGY
" tape," absorbs fluid food, which soaks through its body wall. As the segments at the older end of the animal mature, they are set free and pass out of the alimentary tract, to be picked up, perchance, in the food of an herb- ivorous animal or else to perish.
The economic importance of parasitic worms is very great. Thus, although no great epidemics of the flukes
have occurred in this coun- try, a million sheep are annually lost by this para- site in Great Britain ; and in 1879 and 1880 it was estimated that three million sheep died annually in England alone of this parasite. In Buenos Ayres, during 1882, a million sheep died of fluke disease. By great care in prevent- ing infection, especially during damp seasons, we may be able to prevent
Fi<i. 148.— Cerebratulus, a cream-colored any such disaster ill this nemertean. Head end at upper part of
figure ; mouth turned toward observer, ^Y'
proboscis retracted. Instantaneous The 2'1'OUp of Nemertini
photograph of living worm by W.H.C.P. . n- i >T A
is allied to the flat worms.
It includes chiefly marine animals, of somewhat flattened form and great length, even as great as thirty metres. They protrude a long, slender proboscis. These worms are especially abundant in the sand of the seashore, although land nemerteans occur. Cerebratulus (Fig. 148) is a common form from the east coast.
APPENDIX TO CHAPTER
159
APPENDIX TO CHAPTEPv X
KEY TO THE MORE IMPORTANT FAMILIES OF POLYCH.^TA
a\. Head distinct from trunk ; proboscis protrusible
[wandering Polychseta]. bi. With broad dorsal scales ....
b-2. No scales ; only one mouth-segment.
Ci. Cirri not leaf-like ; body long and not
flattened. d\. Head not segmented.
e\. Jaws composed of many pieces . e-2- Two powerful jaws .
d». Head with its lobes segmented .
c2. Small worms, body flattened, cirri evident
«o. Head not distinctly separated from trunk ; pro- boscis short, not protrusible ; no jaws [seden- tary Polychseta]. bi. Gills, when present, arise either from almost
all, or else the middle segments. GI. Body not separated into various regions ; distinct head ; no antenna ; gills in form of elongated, thread-like cirri
C2. Body divided into 2 or 3 different regions ; no antennal cirri ; proboscis present ; no gills
&2- Gills almost always present and limited to the
anterior end of the body ; no cirri ; body
divided into an anterior and a posterior part.
Ci. Gills confined to the anterior segments ;
head lobe small ; numerous antenna in
2 bunches ; no antennal cirri
c2. Gills confined to head ; 2 inrolled leaves standing at the sides of the mouth
Aphroditidce
(Ex. Lepidonotus)
Eunicidce
Nereidu'
(Ex. Nerds)
Glycerida*
(Ex. Ki
(Ex. Antolytus)
Cirratulidce
(Ex. C'irratulus)
Maldanidaz
(Ex. ClymeiH'llu)
Terebellidce (Ex. Amphitrite)
SerpulidoK
(Ex. Serpula)
CHAPTER XI
THE SLUG AND ITS ALLIES
THE slug belongs to the group of Mollusca.1 This group contains animals which possess two distinctive organs — the foot^ by means of which locomotion is effected, and the mantle, a fold of skin covering over or enclosing a greater or less part of the body. The mantle usually secretes on its outer surface a calcareous shell. Exceptionally, both shell and mantle may be entirely absent in the adult.
Among the Mollusca, the slug occupies the class Gastrop- oda,2 characterized by the possession of a head, which bears feelers and eyes, and an unpaired foot, situated on the ventral surface of the body and used to crawl upon.3 Gastropods are either with or without an external shell. When the shell is present, it is made of one piece, that is, it is univalve^
1 mollis, soft.
- -yao-Trjp, belly, stomach ; TTOUS, foot.
3 A key to the principal families of gastropod shells of the Atlantic coast of the United States is given in the Appendix, p. 174.
4 The three orders of Gastropoda may be distinguished by aid of the following key : —
«!. Breathing by means of lungs ; no operculnm ;
living on land and in fresh water . . . Puhnonnta
a2. Breathing by gills ; chiefly marine.
160
THE SLUG AND ITS ALLIES 161
Slugs belong to the group of air-breathing, land-inhabit- ing gastropods, or Pulmonata.1 They may be found in the spring, summer, and autumn, under wet, decaying pieces of wood, under stones or fruit, in the grass, on the shady side of fences ; in a word, in moist, dark situations. They especially shun sand, ashes, and sawdust, because these substances tend to dry up the mucus which they secrete over their body to retain its internal fluids. Slugs are nocturnal (Fig. 122), hence they have the reputa- tion of being rather rare. During the winter they live in the ground encased in their own slime, but some species frequent greenhouses in cold weather, and in consequence of this habit mav remain active all the year round.
*j «/
The food of slugs consists chiefly of the green leaves of succulent plants, and also of ripe fruit, such as apples. Our largest slug, Lim«.r2 maximus? is easily maintained
?>i. Gills in front of heart ; mantle-complex on anterior side of intestinal sac ; operculum constantly present Prosobranchiata
b-2- Gills behind heart ; if shelled, without oper-
cnlum Opisthobranchiata
Key to the principal families of the American Pulmonata :-
t(i. Eyes at apex of (usually retractile) tentacles.
l>i. With external shell ; 4 tentacles . . . Helicidce
(Ex. Helix)
&2. Without external shell Lhnacidce
(Ex. Limax)
«2- Eyes on inner side or at base of the (non- retractile) tentacles. bi. Thick shell, with thick, often-toothed outer
edge ........ Auriculidce
(Ex. Melumpus)
6.2. Thin shell, with sharp margin . . . Limmndce
(Ex. Pbysa)
1 Provided with lungs ; from pulmo, lung.
2 Aet/xa£, naked snail. 3 Largest.
M
162
ZOOLOGY
in captivity by keeping in a dark box and feeding on the blanched leaves of cabbage. In captivity one individual will sometimes devour another.
Of our three principal species of slugs there may be first mentioned Limax maximus, which gains a length of about 10 centimetres and has a light brown color, marked with longitudinal rows of black spots along the back and sides.
This species was almost un- known in this country until the middle of the sixties, but it is now widespread through- out the East. It has doubt- less been introduced from the continent of Europe, where it is very abundant. Second, Limax ay rest is1 is usually about 2.5 centimetres long ; it varies in color from whitish through gray to black. It is now common in the eastern United States, but is believed to have been introduced from Europe. Third, Limax cam-
genera figured are: A, Actaeon ; pestris? a native species, is B, Aplustrum; C, Cylicbna; D, , ,
Atys; E, Phiiine ; F, Doiabeiia; smaller than agrestis, and
its tuberosities are not so much flattened or plate-like. It occurs widely distributed east of the Rocky Mountains.
Economically, slugs are of importance because at times in some localities they cause much destruction in gardens
1 Living in the field. 2 Living in open fields.
FIG. 149. — Illustrating the transi- tion of form in the shell of certain Opisthobranchs, from the pointed spiral to the almost tiat plate. The
G, Aplysia ; //, Pleurobranchus. Drawn to various scales. From Cooke, " Mollusca."
THE SLUG AND I'M ALLIED
168
.c.d
ep-
and greenhouses. Particularly in Europe, Limax agrestis has often devastated fields of young shoots ; this species is especially fond of bulbous plants.
In the apparent absence of a shell the slug seems to be an aberrant gastropod. Other land gastropods — the snails — have an evident shell. In Limax the shell is reduced to a thin, horny ^ J plate, embedded in the mantle. Between the con- dition seen in the snail and that in Limax there are intermediate condi- tions, in which the large shell is partly covered by the mantle, and others in which the shell has become reduced in size. In allies of Limax -
in
a genus called Ario'ti —
FIG. 149a. — Illustrating the gradual covering of the shell (*7t) in certain Opisthobranchs by the epipodia (ep] and mantle ; c. d, cephalic disc. Drawn to various scales. A, Haminea; /:>, Sca- phander; C, Aplustrum ; I), Aphysia ; E, Philine. From Cooke, "Mollusca."
the shell is reduced to a few calcareous grains. An exactly similar series in the degeneration of the shell is found in certain Opistho- branchs, illustrated in Fig. 149. The beginnings of this process of covering the shell are seen in many gastropods in which the mantle edges may protrude beyond the lips of the aperture, and are folded back over the outer surface of the shell. A more developed condition is seen in species like Aplysia, in which the mantle is permanently reflected.1 In Limax the reflected edges of the mantle
Fig. 149rt.
164 ZOOLOGY
have permanently grown together. The reflection of tl it- man tie seems to be of advantage by affording additional
protection to the visceral mass. But after the complete over- growth of the mantle the shell seems to be useless, and con- sequently degenerates.
The Pulmonata are either terrestrial, like the slug, or aquatic. Of the terrestrial
Fis. ir,o.- shell of Helix, alboia- pulmoiiates other than the
6m, a common forest snail. Nat. slua- the most important are size. Photo, by W. H. C. P.
the snails 01 the genus Helix.1
Helix 2 is noteworthy, because it is richer in species than any other molluscan genus, since it contains over three thousand species. The distribution of the genus is world- wide. In North America the snails are most abundant in limestone regions, consequently they are more numerous in individuals in the South and West than in granitic New England. One of the most interesting species is Helix nemoralis, a European form, which has been intro- duced into our country at Burlington, New Jersey, and Lexington, Virginia. At these places it has multiplied so rapidly, and varied to such a degree, that three hundred and eighty-five varieties have been enumerated from an area, at Lexington, not over one thousand feet in extent in its greatest diameter3 (Fig. 151). Any species of Helix collected in large numbers is apt to show abnor- malities in the number of tentacles and of eyes upon the
1 e'\i£, a turning round, as in spire of snail shell. 2 Fig. 150.
3 See paper by Professor J. L. Howe, in American Naturalist, Decem- ber, 1898,
THE
A NT) TTS ALLIES
165
tentacles. Besides Helix, a very abundant cosmopolitan land pulmonate is Pupa.1 Being of small size, it is, how-
Fi<i. 151. — Helix n?)n-jralix, from Lexington, Va., collected by Professor J. L. Howe, showing variation in stripes. Upper line, first figure, normal form, 5 stripes; other figures of first and second lines show reduction of stripes; third line shows broader (and fewer) stripes (the last figure is very dark and is poorly reproduced). The shells in the lowest line show more than five stripes. From a photograph; reduced one-half.
ever, less commonly known. It is found in woods under leaves or in old stumps and decaying logs, where it feeds. The shell is many times whorled, and has a blunt apex.
Intermediate between the terrestrial and aquatic pulmonates is the family Auriculidye, the members of which live on the seashore,
in salt marshes or 011 rocks where they FlG- 152- • Me~ , i-i lampus,the salt-
may even be immersed in brackish water marsh snail.
A little girl or doll.
Nat. size. Photo, by W.H.C.P.
166
ZOOLOGY
at high tides. One of the commonest forms is Melampus (Fig. 152), found among the roots of marsh grass.
Of the aquatic pulmonates three genera are common and easily distinguishable. Limnaea,1 the " pond snail," is com- mon in ditches and muddy or stagnant ponds. Its shell runs up into a sharp spire, and is right-handed, i.e. hold- ing the shell so that its aperture is next the observer and below, the aperture is at the right (Fig. 153). Limnpea crawls over the bottom, up the stalks of aquatic plants, and 011 the sur- face film of water. During- FIG. loo. — Left. Physa hetcro-
stropha, the left-handed pond drought it burrows into the snail Right Limn^a, the right- d d j tj t f
handed pond snail, with the
apex eroded off as is usually the the shell.
Physa2 has a smaller, rela- tively stouter shell than Lini-
, and one whose coil is left-handed (Fig. 153). It lives in even the smaller ponds and brooks, and may be easily reared in aquaria. It feeds freely upon any kind of vegetable matter. Pliysa lieterostropha is the common species of the United States (Fig. 153, left).
Planorbis8 is coiled in one plane like a watch spring1.4 It lives in a similar ,,
FIG. Io4. — Planorbis,
habitat with Physa. A great many the Mat-coiled pond species are distinguished which vary con- pj^jto bvWHcTp siderably in size. Snails of this genus likewise are easily kept in the aquarium, and lay numerous
case in adult shells. Nat. size. Photo, by W.H.C.P.
1 From Xt/x^Tj, a marsh.
2 00cra, bellows.
s planus, flat ; orbix, circle.
Fig. 154.
THE SLUG AXD ITS ALLIES 1(37
eggs encased in gelatinous envelopes adhering to the glass.
Of the shells of marine gastropods, which are favorite objects in collections because of their beauty and per- manence, only a few types can be mentioned.
Littorina 1 is an example of the entire-mouthed proso- branchs. The commonest form at most parts of the shore- line north of New York at the present time is Littorina2 littorea.2 This is knoAvn in England as the periwinkle, and is there used as food. As its systematic name implies, it occurs on the seashore, which it often crowds so as to force all other species from it. It occurs north to Greenland, and on the northwestern European coast. It has not always FIG. 155. — Littorina ut- occupied our shores, but has been £Tf !he sh£re tsnf '
Nat. size. Photo, by
migrating southward. In 1855 Lit- w. H. c. P. torina \vas found in the Gulf of St. 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 Hampshire coast ; in 1872 one specimen was found at Salem, Massa- chusetts ; in 1875 the first two specimens were taken at Woods Hole, Massachusetts, south of Cape Cod ; in 1880 the first specimen was taken at New Haven; in 1891 it occurred as far south as Delaware Bay. Yet at the present time it is not very abundant at Cold Spring Harbor, near the western end of Long Island Sound. Persons who live on 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
tia) her os. nat. size. W. H. C. P.
Two-thirds Photo, by
shore-line. Besides littorea there are two species of Littorina which were on our coast when records first began to be made. The species may be distinguished by the circum- stances that L. littorea has a black head and a heavy shell of brown or olive color. L. rudis l is smaller, has an angle at the apex of 60° to 70°, and its shell varies in color from white to red. L. palliata2 has an FlG m.- Natica (Luna- apical angle of 95°, and a shell varying 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 at the left of the mouth and in the axis of the shell (Fig. 156). In the living animal the shell is often quite envel- oped by the large fleshy foot. The members of this genus lay their eggs in spiral " collars ' made of aggluti- nated sand. These are common objects of the seashore.
Fulgur 3 is a good example of a prosobranch having a canaliculated shell. The canal exists for the pur-
r (Sycotypus) cani- Pose of containing the siphon ^ by culatus, one of the which water is brought to the animal
Fasiolaridse. One- ,. . -. . -, T^ ,
fourth nat. size. Photo, as it lies buried in the sand, bulgur by w. H. c. P. is OU1. largest common gastropod. Its
1 Hough, rude, 2 A cloak. 3 Lightning-.
FIG. 157. — Shell of Ful-
777 A; HLUG AND ITS ALLIES
IfW
shell is about 150 millimetres long, and pear-shaped. In
one species the margins of the whorls are grooved (Fig.
157) ; in the other they are carried out
into thorns. The egg-cases are tough
and membranaceous and resemble rows
of coin strung on a string, the whole
being slightly coiled.
In Urosalpinx 1 the canal is short (Fig. 158). This typical representative of the Muricidse is everywhere abundant on our Eastern coast. It is much hated by
«/
oystermen, by whom it is known as the
"oyster drill." It bores through the FIG. 158 - - Urosal-
J pinx, the oyster
shell of this and other bivalves bv means
*/
of its radula and sucks out the contents through the hole.
Crepidula,2 the boat shell or " decker," represents a type in which the spire has become almost obsolete. It is
drill. Nat. size. Photo, by W. H. C. P.
FIG. 15U. — Crepidula, the boat shell. Two-thirds nat. size. Photo, by
W. H. C. P.
still represented, however, in a rudimentary way at the left of the aperture (Fig. 159). The modified shape is associated with the habit the mollusk has of lying, aperture down-
1 ovpd, tail ; adXiriy^ a trumpet. - A small sandal (crepidcC).
170
ZOOLOGY
ve
sh
m.e
~nu
mu
ward, close to the rock or another shell. By this means the animal is better protected. The "deck'' is a plate
which has been de- veloped internally to help hold the animal in the shell.
The limpets are modified prosobranchs. They are bilaterally symmetrical, and are covered by a flat, coni- cal shell, which is ap- plied closely to the rock all around the base in such a way as to pro- tect the animal within. In some species (genus
_
* ISSUrella a) there IS an
lamellse; m.e, edge of the mantle; mu, at- opening" at the apex of tachment muscle; si, slits in the attachment
muscle; sh, shell; v, efferent branchial the shell through which vessel ; V aorta -,ve .smaller vessels. From th t { expelled
the " Cambridge Natural History."
which has passed over
the gills, Our common Eastern rock limpet is not per- forated; it is known as Acmcea.2 In Europe, limpets (Patella, Fig. 160) are used as food ; but on our Eastern coast they are too rare for this.
The opisthobranch mollusks include a large proportion of symmetrical shell-less species. The most familiar of these are the nudibranchs. They may be found among hydroids hanging from rocks, or in tide-pools. Our species are usually less than 20 millimetres long. They are often
1 A little slit or fissure. '2 d/c/mtoj, in full bloom, maturity.
FIG. 160. — Patella vulgata, seen from the ventral side. /, foot ; y.l, circlet of gill
THE SLUG AND ITS ALLIES
171
covered with numerous gills, which give them a velvety aspect. When placed in an aquarium, they lay eggs in gelatinous coils on the hydroid stems. Eolis l is a com- mon genus (Fig. 161 J.
Besides the gastropods, two groups of mollusks may be briefly mentioned here. In one group the body is very
symmetrical, not only
externally, but also
internally, which is
not true of most
symmetrical gastro- FIG. 102. - chiton
FIG. 161- "Eolis (Cra- d A common (Trachydermon)
turn), a nudibranch. apieulatux, the ar-
Nat. size. Photo, of representative IS Chi- madillo snail. Nat
living animal by W. H. ^ 2 (Fig> 162) _ Thig ^ ^Photo. by
animal has a sort of
coat of mail, since its shell is made up of eight pieces, lying one behind the other, along its back. When removed from the rock or shell on which it rests, it coils up like a pill-bug or armadillo.
Coordinate with the Gastropoda is the group of Cepha- lopoda.3 In this group belong the squids and cuttlefishes. They have a large, distinct head, a circle of arms about the mouth, a funnel-shaped foot, and huge eyes on each side of the head (Fig. 163). The squids are the best-known cephal- opods, since they travel in schools in our harbors and are often cast upon the shore after a storm. They can also be obtained in the markets of our coastwise cities, since their flesh is used to a certain extent as food. Cuttlefishes,
1 Eolis, daughter of Eolus, the god of the winds. ~ xircji', coat, case, covering.
3 Ke(pa\r), head ; TTOI/S, foot ; because the arms or foot are placed around the mouth.
172
ZOOLOGY
best known from their "bones" or rudimentary shells
\j
embedded in the mantle, are inhabitants of deeper
waters. They have shorter bodies than the squids, and their arms are eight in number instead of ten as in the case of the squids. In both groups locomotion is effected by the reaction to a stream of water which is taken into the mantle chamber at the edges of the mantle and is forced out through the " funnel," which lies between the eyes in Fig. 1(33.
The shell is rudimentary in both the squids and the cuttlefishes, and like that of the slug is embedded in the mantle. Even in Spirilla the shell, though coiled and containing a siphon, is completely covered by the skin of the animal. There are two liv- ing genera of Cephalopoda which have an external shell. One is an ally of
FIG. iitt. — L<jiit/<j Peaia, the cuttlefishes — the paper nautilus
eastern squid. One-third t ^ii'i--C i • n
nat. size. From Rathbim. O1> Argonauta? which IS found in all
tropical seas. The other is the sole
survivor of a once abundant group. This is the Pearly Nautilus of the Indian and Pacific oceans. Its shell is di- vided into water-tight compartments, in the last formed of which the animal lies. It keeps its attachment to the shell by means of a central strand of tissue — the siphon (Fig. 164, s). Allied to the Nautilus is the huge
a sailor in the Argo.
THE SLUG AND ITS ALLIES
173
family of Ammonites, of which two thousand species are known, ranging from the Silurian up to the Cretaceous formations.
FIG. 164. — Nautilus pompilius, the Pearly Nautilus. Median section, c, outer- most chamber whose bottom is formed by the septum, tie ; s, siphon travers- ing all compartments ; ?,eye; h, hood; rn, part of mantle, reflected over the shell ; /, lobes enclosing tentacles (t) ; si, incomplete funnel ; mu, shell muscle ; n, gland secreting the capsules for eggs. After Owen.
174
ZOOLOGY
APPENDIX TO CHAPTER XI
Spirulidw
VermetidcB
KEY TO THE PRINCIPAL FAMILIES OF MARIXE-SHELLED GASTROPODS OF THE ATLANTIC COAST OF THE UNITED STATES, ADAPTED FROM A. C. APGAR
a i. Shell spiral, of one to many whorls.
61. Spire in a single plane, and whorls not in con- tact. [A cephalopod shell ; liable to be mistaken for a gastropod-shell, page 172] bo. Spire dextral.
Ci. Operculated ; aperture not over \ area of
shell.
d\. Anterior margin of aperture entire. €i. Shell tubular ; spiral at apex, irregularly twisted near aper- ture ..... e>2. Shell regularly spiral, elongated ; width less than 1 length ; whorls 5 or more ; angle of spire less than 45° ; aperture less than ^ length of shell, /i. Whorls rounded , almost sepa- rated, crossed by elevated longitudinal ribs ; aperture oval ; lip continuous ; our species over 10 mm. long . /2. Whorls about 5; minute shell, less than 5 mm. long ; width about | length ; aperture about i length ; apex blunt /3. Whorls 5-10 ; shells elon- gated, conical, turreted ; aperture ^-| ; length of shell of our species 4-10 mm. long .... 63. Shell regularly spiral, shortened ; width nearly as great as or greater than length ; whorls
ScalariidcB
Rissoidce
Pyramidellidce
APPENDIX TO CHAPTER XI
175
usually few ; angle of spire always over 50°, usually over 90° ; aperture over \ length of shell.
/i. Shell conical, pearly under epidermis and within aper- ture, usually brilliantly so ; umbilicus deep and large . /2. Shell globular or oval ; spire short, body whorl large ; umbilicus rounded, dis- tinct, either free or covered by a callus ; angle of spire 90° or more
/a. Shell top-shaped to globular ; interior pearly, 8-30 mm. long ; umbilicus when pres- ent not rounded nor cov- ered with a callus .
/4. Shell minute, nearly disk- shaped, widely umbilicated Anterior margin of aperture notched
or produced into a canal. e\. Shell with canal formed by a de- cided prolongation of anterior end.
/i. Large, heavy shells, over 100 mm. long, pear-shaped ; whorls angulated or nodu- lous
/2. Rather thin shells, 20-80 mm. long, ovate to pear-shaped ; whorls rounded and cov- ered with 40-00 small re- volving ridges . .
/s. Shells over 20 mm. long, with longitudinal, rib-like undu- lations crossed by revolving lines .
Trochidcv
Naticidae
(Ex. Natica)
Littorinidce
(Ex. Littorina) Adeorbidce
Fasciolariidce
(Ex. Fulgur)
Bwcinidce
Muricidw (Ex. Urosalpinx)
176
ZOOLOGY
/4. Shells less than 20 mm. long ; aperture with a notch near posterior end, formed by outer lip not squarely meet- ing body wall .
fr,. Shells less than 15 mm. long ; aperture entire at posterior end ; narrow, and a little less than -J the length of the shell ; canal rather short . .*
e-2. Canal short or absent ; aperture
notched, /i. Shells large, 40 mm. or more
long ; whorls rounded /2. Shells 20-40 mm. long;
whorls rounded
/3. Whorls flattened, surface usually beaded ; aperture over i length of shell
Co. Non-operculated, or operculum very mi- nute ; aperture with neither a canal nor a notch at anterior end. (I i. Aperture over f area and f length of shell ; spire distinct, pointed ; shell ear-shaped ..... (?o. Aperture \ the area or more, and the
full length of the shell. Ci. Shell with 1 whorl, less than 2 mm. long .... ?o. Shell with several whorls, under
4 mm. long ; spire flat . e-s. Several whorls, a pit in place of
spire, over 6 mm. long . t?s. Aperture less than ^ the area of the
shell.
e\. Aperture | to whole length of shell ; spire distinct, usually flattened ; under lip with single fold or smooth
Plwirotnmidce
Columbellidce
Philinidce, Scaphandridce
Bull idee
TornatinidoB
APPENDIX TO CHAPTEE XI
177
?2. Aperture i-f length of shell ; under lip with 2 or more teeth
c3. Non-operculated ; aperture with canal at anterior end ; our species 20 mm. or
less long
b3. Sinistral ; whorls in contact.
<"i. Shell ovate-globose, small, not over 5 mm. long, transparent ..... c.2. Shell elongated, turreted, slender, less than oO mm. long. .... GS. Shell large, over 100 mm. long, with pro- duced anterior canal . a-2. Shell flat, boat or cup shaped, if somewhat spiral,
not forming a complete whorl. bi. Shell with apex somewhat spiral and an in- ternal, usually horizontal, partition or dia- phragm
fto. Shell conical or cup-shaped, with apex turned
forward ; no shelf or partition. GI. No perforation at apex or notch in mar-
gin
c-2. Apex recurved ; margin or apex perfo- rated . . > . . .
Auriculidce
(Kx. Mt'lunipiis)
Triforidce
Calyptrwidce
(Ex. Crepidiila)
Acmceidce
(Limpets)
Fissurellidce
N
CHAPTER XII
THE FRESH-WATER CLAM AND ITS ALLIES
THE fresh-water clams belong to the group of lamelli- branch mollusks, characterized by the absence of a distinct head, by the possession of leaf-like gills on the sides of the body, and by the presence of a calcareous shell composed of a right and a left valve. Economically this group is the most important to man of all Mollusca. It includes both marine and fresh-water species. About six thousand species of living lamellibranchs and over ten thousand fossil species are recognized. They all fall into two prin- cipal subdivisions. The first (Siphonata) includes species which possess a siphon and have the mantle edges grown together, while the second (Asiphonata) has no siphon and has the mantle lobes for the most part wholly separated.1
Anodonta and Unio are extremely common in the ponds, lakes, and rivers of North America. Anodonta is more apt to be found in still waters and Unio in running waters. They lie partly buried in the mud of the bottom, with the valves of the shell gaping open and the partly united edges of the mantle protruding. They do not lead wholly sedentary lives, but may burrow or plough along the bottom.
Their food is gained from organic particles borne along
1 A key to the principal families of bivalve shells will be found in the Appendix, p. 188.
178
THE FRESH-WATER CLAM AND ITS ALLIES 179
in the current of the water. A part of this current is carried through the mantle chamber and forced out again, deprived of usable food and of the oxygen used in respira- tion. By devouring organic matter these clams act as useful scavengers of the water.
The family of Unionidae, to which Unio and Anodontia belong, is of world-wicte distribution, but nowhere else are Unionidre so numerous as in the United States. They show in our country a most marvellous variability also, so that hundreds of kinds have been described from our waters. The extraordinary abundance of Unios in North America is due to the fact that nowhere else is there such a large area of soluble limestone as in our Mississippi valley. The clams take from the water the lime which they use in the construction of their shells, change it into an insoluble form, and thereby advantageously reduce the amount of the inorganic matter in solution, for this change in the quality of the water renders it more fit to drink and to sustain other animal and plant life.
Although numerous and of large size, the Unionidae do not seem to be much used as human food. The aborigines, however, made use of them, as the great shell-heaps on the banks of rivers of the Ohio valley testify. They yield also pearls, which occasionally, especially in the Ohio valley, are of precious quality. Even the small, imperfect pearls are of value, since they are ground up to make the powder used in polishing the more valuable pearls.
The spawning season of our Unioimhe is short. The eggs pass, during the latter part of October, into the gills of the parent, where they undergo their early development, protected by the parent shell and supplied richly with oxygen. The cleavage is unequal because of the larger
180
ZOOLOGY
amount of yolk in some of the cells than in the others. Eventually a shell is formed, which divides into two valves united by a straight hinge. A spine is formed on the free edge of each valve, and a thread (byssus thread) is secreted from the body. The young at this stage is known as Glochidium (Fig. 165). In the spring Glochidia become free from the mother, and attach themselves to the gills or fins of a fish by means of the spines on the shells. Here they become transformed. The single adductor muscle dis- appears, and becomes replaced by the two characteristic of
' R B. J.
TD. --
FIG. Ki"). — A, advanced embryo of Anodonta: B, free glochidium. /, pro- visional byssus ; s, sbell ; .s7t, books ; .sm, adductor muscle ; so, sense organs ; w, cilia. From Korschelt and Heider's " Embryology."
the adult; the gills arise, the shell gains its adult char- acter, and becomes free from the fish on which it has lived temporarily as a parasite.
There are other species of fresh-water lamellibranchs besides the Unionidae. These belong to the Cycladidae, allies of the marine Cardidre or Veneridre. They have much the shape of our common hard-shell clam of the sea, but are much smaller in size, rarely exceeding 15 milli- metres. Cyclas (or Sphserium) is of world-wide distribu-
THE FRESH-WATER CLAM AND ITS ALLIES 181
tion, but it is especially abundant in North America. It occurs in ditches, ponds, and rivers of New England, as well as in the South and West Some species of it inhabit brackish water. Pisidium has both valves unsymmetrical. Its species are still smaller than those of Cyclas, rarely exceeding 10 milli- metres. It likewise is found in ditches, ponds, and streams all over our country.
The remaining families which we shall consider come from the sea, and all occur on our Eastern coast.
The Pholadidae1 and Teredidae2 include certain wood and rock- boring species, which do great damage by boring into wooden vessels and pilings (Fig. 1(3(3). In such locations they are commonly called ship-worms. The boring is done by the movements of the shell, combined with the action of the muscles and foot. The only thing which seems effectively to stop these mollusks from boring into wood is iron rust, so that piles driven full of nails are apt not to FKJ. KM;.— TV/WO ncpali*,
11-1 in a piece of timber. /'.
be attacked. paUe£. SjSt siph,,lls: T,
tube; V, valves of shell.
1 0oAds, Greek name for a boring mussel. From the " Cambridge
2 repe'w, to bore. Natural History."
182 ZOOLOGY
The Solenidse1 include the "razor-shell" (Fig. 167). This animal, like the shell, is elongated and subcylindrical. By means of its foot, which can be protruded between the
FIG. 167. — Emis direct us. Young. Nat. size. Photo, by W. H. C. P,
\alves, it excavates, with great rapidity, a hole in the sand or mud, into which it draws itself. These mollusks are sometimes used for food, but it is not easy to get them in quantity.
The Mactridae2 include species commonly known in the North as hen-clams and surf-clams. They are more ellip- tical and larger than the common hard-shelled clam or " quo- hog," and have a proportionately lighter shell (Fig. 168). They are not often used as food because they become very tough when cooked.
The Myidae3 include the common clam of New England, Mya arenaria, abundant along our whole Eastern coast and used as food chiefly in New England. These clams occur in great numbers in every mud-flat. Their great siphon is extended at high tide to the surface of the ground, so as to take in and throw out water (Fig. 169) ; but at low tide it is retracted, and the clam lies invisible in its burrow. This clam was much prized by the Indians, as the great, ancient shell-heaps along the coast testify. In 1892 the clam com-
, a channel or tube. 2 /xd/crpa, a baking-trough.
3 fj.va, Greek name for a kind of mussel.
THE FRESH- \VATER CLAM AND ITS ALLIES 183
merce for New England was estimated to be worth nearly half a million dollars.
FIG. Iti8. — Mactra solMisshna, the Eastern hen clam. Nat. size. From
Gould-Binney.
The Veneridae l include the hard-shelled clam or u fjiio- hog " of the Indians. Venus mercenaria is the commonest species, and is most abundant south of Cape Cod. It owes
FIG. 1G9. — My a arenaria, the New England " clam." At the left the foot is seen ; at the right, the siphon. One-half nat. size. From Yerrill. " Inverte- brates of Vineyard Sound."
1 Venus, the goddess of love.
184
ZOOLOGY
its name " mercenaria " to the fact that the purple-colored patch seen on the margin of the shell was used as money
FIG. 170. — I'e/ias mei\"jiuifi<i, the hard-shelled clam. At the left the foot protrudes from the shell ; at the ri^ht the siphons. Nat. size. From Verrill, " Invertebrates of Vineyard Sound."
( " wampum ") by the Indians. The shell is extremely heavy, and usually nearly circular in outline (Fig. 170).
The Arcidae 1 and their allies include several species hav- ing a more or less elongated hinge - joint crowded with many small teeth. Our com- mon Eastern species (Area pe.rala, Fig. 171) has bright red blood and is commonly known as the " bloody clam." The Mytilidae 2 include
Fi(i. 171. — Arcapexatu, the bloody
clam. Nat. size. Photo, by the mussels, which are the
W. H. C. P.
1 area, an ark.
2 /xirri'Xos, an edible mussel of the Greeks.
THE FREtiH-WATER CLAM AND 77'N ALLIED 185
familiar blue-black, wedge-shaped shells attached in clus- ters or beds to rocks near low tide (Fig. 17:2). They are edible. In France they are reared for the market on woven nets, which are submerged at each tide.
FIG. 172. — A bed of Modiola, the horse-mussel, ou a mud-bank. Photo, by
W. H. C. P.
The Aviculidae l are a group closely allied to the last, but not represented, on our shores. It is important because mollusks of this family produce the best pearls. Pearl- lishing has been carried on since the earliest preserved historic records. The pearl banks of Ceylon are known
1 A small bird (acts).
186
ZOOLOGY
to have been fished for two thousand years. The finest pearls come from the Persian Gulf. They are gathered there by native divers, who, after taking several deep inspirations, either dive down unaided or descend upon weighted ropes. When they can no longer remain under water, they either ascend again unaided or are rapidly drawn up to the boats above. The pearl oysters brought up to the surface are then examined for pearls. The pearl is the secretion of the oyster about a small foreign body,
such as a grain of sand. This secretion prevents the irritant from injuring the tissues. It is of the same nature as the substance lin- ing the shell. The latter is the mother of pearl of commerce, and is used for knife handles, buttons, and the like. The iridescence
FIG. 173. —Pectenirradians, scallop, is not due to the chemical
left or upper valve. Nat. size, composition of the secreted
Photo, by AV. H. C. P.
substance, but to the fact
that it is deposited so as to leave fine lines on the surface which diffract the light.
The Pectinidae l include the scallop-shells. These occur along our whole coast. They live in shallow water, and are capable of rapid movement in the water by clapping the valves. The adductor muscle of the valves alone is eaten by man. The common species is Pecten irradians. It varies greatly in color, from bluish to reddish and orange (Fig. 173).
1 pecten, coinb.
THE FUEMl-WATER CLAM AND ITS ALLIES 187
The Ledidae include certain elongated shells with a shiny epidermis, and a large number of teeth on the hinge, which are found chiefly in mud in rather deep water. The animal has a large foot (Fig. 174) with which it bur- rows rapidly. It can also move rapidly through the water as the scallops do.
The Ostreidae : include the oysters, which are the most important invertebrate food fishery, being valued at twenty to thirty million dollars per year for our Atlantic seaboard. Oysters are found on all coasts. Our Ostrea vir- giniana2 extends from the Gulf of St. Lawrence to the Gulf of Mexico. The o}rsters of our Western coast are not so important as the Atlantic species. 0. edulis is the prin-
FKJ. 174. --Yoldia, one of the Le- dida*. Foot protruding below. Nat. size. Photo, by W. H. C. P.
FIG. 175. — Oxtrea virg/niarta, the Eastern oyster. One-third nat. size.
Photo, by W. H. C. P.
cipal European species. In Japan there is a species occa- sionally gaining a length of three feet. The oyster was formerly commoner and larger north of Cape Cod than
1 From Greek name for oyster.
2 Fig. 175.
188
ZOOLOGY
it is now, for the great aboriginal shell-heaps (*' Kitchen- middens ") of the New England coast contain shells of enormous size. The cause of this gradual extinction of the oyster is uncertain, but is believed to be due partly to general climatic and geographic changes and partly to over-iishiiip\
o
APPENDIX TO CHAPTER XII
KEY TO THE PRINCIPAL FAMILIES OF MARINE LAMELLIBKAN- CHIATA OF THE EAST COAST OF THE UNITED STATES
ADAPTED FKOM A. C. APUAK
a\. Shell when closed at ventral side, gaping inure or
less at the ends.
bi. Without toothed hinge or proper ligament, often with accessory valves ; no distinct epi- dermis.
c'i. Length decidedly greater than height Co. Length and height nearly equal ; shell small .......
b-2- With proper hinge, often distinctly toothed
and with hinge ligament or pad. t*i. Hinge with many small cardinal teeth in each valve . .
c-2. Hinge of not over 4 cardinal teeth in
each valve. di. Shells equivalve.
e\. Two or more times as long as high, gaping more or less at
ends. /i. Length '•> to-0 times height ;
epidermis polished ; um- bones not over one-quar- ter from anterior end
Pholadidcc
7.eredid(e
(Shipworms)
Ledidce
(Ex. Y old in)
Solenidce
(Uazor Clatus)
APPENDIX TO CHAPTER Xll
189
/:>. Shell thin, rounded in front, narrowed and gaping be- hind, cartilage pit shal- low ; external ligament short .... Shells inequivalve. e\. Length and height about equal, e-2. Length decidedly greater than
height.
/!. Over 25 mm. long ; right valve nearly flat ; whole shell compressed to one- sixth length .
/2. Over 50 mm. long ; 'slightly inequivalve ; no external ligament; internal car- tilage on spoon -shaped process of left valve
f.2. Length about 3 times
height ; umbones central, Psammoliidfc fs. Length less than 3 times
height ; surface covered
with radial ridges, chalky
white, umbones near an- terior end /4. Length about 2 times
height; epidermis
polished, with notched
border extending beyond
the edge of the thin shell, /4. Shell with thick black
epidermis ; external liga- ment prominent and on
shorter end of the shell, e». Length less than twice height. J\. Shell somewhat triangular,
with internal cartilage
between deep triangular
pits, similar in each
valve
Solrmyidw
SaxicctvhUv
Mactridce
(1 leu Clams)
Pmidoriflre
190
ZOOLOGY
/3. Shell under 18 mm. ; promi- nent external ligament, «2. Shell not at all gaping
bi. With not over 3 cardinal teeth in each valve. t'i. Valves equal in size, curvature, and
markings.
di. Anterior muscular impression very small, hinder large; shell elongated, mussel-shaped ; umbo at or near posterior end ....
d». Hinge line straight, formed by ears at sides of umbo, radiating ribs, scalloped edge ....
d$. Height and length nearly equal ; a decided pallial sinus
(Hi
d±. Height and length nearly equal ; no distinct pallial sinus, at most a mere undulation of pallial line at posterior end.
f\. With a plain lunule in front of umbones; without radial ribs. fi. Over 20 mm. long, com-
«/ *• O 7
pressed , ligament external /_». Shell somewhat quadrant shaped; less than 8 mm. long; surface with con- centric ridges.
/s. Shell less than 5 mm. long, very much compressed ; ends rounded .
e2. With no lunule and with dis- tinct radial ribs . Co. Valves unsymmetrical.
(?i. 2 muscular impressions, a distinct
pallial sinus. (See t?2 under «!.) d». 1 muscular impression ; height never much less than length
Tellinidce
Mytilidce
(Mussels)
Pectinidce
(Scallops)
Veneridce
inl-shelled Clams)
As t art i < he
Crassatellidce
ErycinidcK Oardiidce
APPENDIX TO CHAPTER XII
191
€]_. Fixed mollusks with large rough shells attached by large valves,
€'2- Fixed mollusks, with their pearly shells attached by smaller valve which is flat or concave and perforated or notched
e*. Free mollusks ; hinge line
straight, formed by ears at
sides of umbo ; with radial
ribs .....
With many small cardinal teeth in each valve.
Ci. With distinct radiating ribs ; shell over
30 mm. long
Co. Smooth, length and height equal ; under 12 mm. long
c3. Elongated shells, length nearly or twice height ; a pallial sinus ....
Ostreidce
(Oysters)
Anomiidce
(Jingle shells)
Pectinidce
ArcidoK
(Ark-shells)
NucnlidcK Ledidce
KEY TO THE PRINCIPAL GENERA OF FRESH-WATER LAMELLI-
BRANCHIATA
«i. Siphonate ; without marked muscular impression,
Fain. Cycladidce bi. Valves sub-symmetrical ..... Genus Cyclas
b>2- Valves unsymmetrical ; siphons united . • . Pisidium
cto. Asiphonate ; with two muscular impressions . Fain. Unionidw l)\. Hinge with teeth.
Ci. With short cardinal teeth and long lateral
teeth ....... Unio
Co. With short cardinal teeth and no lateral
teeth ....... Maryaritana
Hinge without teeth, or with only a small ridge, Anodonta
CHAPTER XIII
THE STARFISH AND ITS ALLIES
Systematic Position. — The starfishes belong to the group of Echinodermata,1 characterized by a radial, usually five-rayed, structure, a more or less well-developed system of calcareous plates in the skin ; a system of water-tubes, which is used by the movable forms for locomotion; and the separation of the intestine from the body cavity.
Distribution and Habitat. — The common pink starfish of the eastern United States (Asterias2 vulc/aris3) ranges from Labrador to northern Florida. A dark brown form, sometimes called Asterias Forbesii^ is recognized by some authors as a separate species inhabiting the coast from Massachusetts Bay southward. Our shore starfish extends out into fairly deep water, but is not abundant at greater depths than 60 fathoms. In Long Island Sound it is found especially on. the oyster beds, where it is very destructive. On rocky coasts starfishes will be found in crevices of the rock or in tide-pools. They love cool waters, and are often found hanging on vertical walls or ledges. Upon reaching the surface of quiet water, they may extend one or more of their arms out upon the under side of the surface film.
hedgehog, sea-urchin ; Se'p/xa, skin. A key to the principal classes of Echinodermata will be found in the Appendix to this Chapter. - dcrT^p, star ; dtrrepias, starred.
3 Common. 4 Of Forbes, an English zoologist.
102
THE STARFISH AND ITS ALLIES 193
Food. - -The favorite food of the starfish is some kind of mollusk, especially bivalves, such as mussels and oysters. Their method of feeding is as follows: They crawl over the bivalve, arch the body over it, apparently pull open the valves, then turn the stomach inside out over the soft body within the shell, and gradually digest it. The star- fish probably finds its food by means of a keen chemical sense.
Starfishes are of economic importance on account of their destructiveness to oysters, but since the oystermen have learned to keep the beds clear of starfishes and that tear- ing starfishes into pieces only aids in their increase, as each piece produces a whole starfish, the damage wrought by starfishes must be less than it was formerly.
Development. - - Starfishes have the sexes distinct ; and the sex can usually be told by the color. The female has a more bluish tint, while the males are of a reddish brown color. Both the eggs and sperm are extruded into the water through small openings on the aboral surface at the interspace between two adjacent arms. The egg is hardly visible to the naked eye, and is enclosed in a delicate membrane. The egg undergoes cleavage ; that is to say, the single sphere breaks up into two, four, eight, sixteen spheres, and so on. Finally a hollow ball, made up of these spheres or cells, is formed, called the "blastula." Next the wall of this hollow sphere is pushed in at one side, forming a sort of cup with two walls. This is the so-called "gastrula." The cavity of this cup is the digestive cavity. At first it is a sac with only one opening, but later a second opening, the true mouth, breaks through, and the former opening persists as the anus. Pairs of arms, edged with cilia, now bud out on o
194 ZOOLOGY
each side of the body, and the larva becomes bilaterally symmetrical.1 Meanwhile, inside the body, the system of water tubes of the adult starfish has begun to form, and finally, over the stomach on the left side, five main water tubes, radially arranged, make their appearance ; these are the five radial tubes, one of which runs down each future arm.2 On the right side of the stomach, calca- reous plates are laid down to form the aboral wall of the starfish.3 The young star is now found as a parasite at the hinder end of the larva. Soon all the front end of the larva, together with the long arms, becomes absorbed. Up to this stage the larva lias been free-swimming, but it now settles to the bottom. There the process of resorption is completed, the upper and lower surfaces of the star approach each other, the calcareous skeleton and sucking- feet rapidly develop. At this stage the disk is so large, and the arms so short, that the young starfish looks more like a sea-urchin than an adult starfish. The elongated arms and the pedicellarue of the adult are not gained until three years have passed.
t/ -*-
1 Figs. 176 and 177. 2 Fig. 178. Fig. 179, ab>.
FIG. 176-179. — Larval stages and metamorphosis of starfish. After drawings of E. B. Wilson, from Brooks, " Invertebrate Zoology."
FIG. 176. — Dorsal view of starfish larva with beginnings of ciliated arms.
FIG. 177. — Ventral view of same larva.
FIG. 178. — Side view of an older larva in which young star is beginning to arise.
FIG. 179. —Ventral view of same larva, a, anterior end ; b, posterior end; 1-4- , ciliated projections; a', preoral arms; a HI, oral surface of young star with beginning water tubes, am-am5; ab, ub', ab^, aboral surface of star; c, postoral arm ; i, intestine; m, mouth; n, lateral arm ; o,anus; ce, oesopha- gus; q, q', dorsal lateral arms; *, stomach; ww', water tubes ; am, Fig. 177. region from which water tubes arise.
om
FIG. 17ti.
FIG. 177.
FIG. 179.
195
196
ZOOLOGY
Abnormalities are frequently found among starfishes, —
partly on account of their capacity for regeneration, even from the disk and a single arm. Thus one may find a starfish with three or four rays, or with a small ray interpellated in be- tween normal-sized ones. Not all abnormalities seem to be the result of mutila- tion, however; for example, sometimes two arms seem
FIG. 180. — Abnormal starfish (Astenas), apparently produced by fusion of two to be fused (Fig. 180).
r°Thalf nat- size> Phot°* by Other Starfishes. — Aste-
. \j, -T.
FIG. 181. — Ct'ibrella sanguinolenta. Nat. size. From Leuuis.
THE STARFISH AND ITS ALLIES
197
rias vulgaris belongs to the gionpAsteroidea.1 But there are over five hundred other species of starfishes. In some of these — as in Asterias — the skele tal plates of the skin make a net work ; in others they form a solid calcare- ous covering. To the first class belong, besides Asterias vulgaris, Aste- rias ocliraceaf which oc- curs commonly on the Pacific coast from Sitka, Alaska, to San Diego, California. This has a much thicker, more
solid skin than the FIG. 182. — Solaster, a multirayed starfish.
t ,-, , . . A Reduced. From Leunis.
Atlantic species. A. gi-
gantea^ attains a diam- eter of over two feet. Next to A. vulgaris, our commonest Eastern species is a smooth, leathery, blood-red star- fish, about 10 centi- metres in d i a m e t e r,
called Oribrella 4 san-
1 APT-TIP, star ; eTSos, form.
2 o>x/>6s, pale yellow.
3 giyanteus, gigantic. This species occurs on our Pacific
FIG. 183. — Archiaster, a webbed starfish. coast. Slightly reduced. Photo, by W.H.C.P. 4 cribrum, sieve,
ZOOLOGY
guinolenta1 (Fig. 181). Certain starfishes have many arms instead of only five, as in the case of Solaster 2 endeca 3 of the northern Atlantic (Fig. 182). In still other star- fishes the rays are partially connected by a membrane like the web of a duck's foot, so that the whole outline is nearly pentagonal (Fig. 183).
The Ophiuroidea. — In the Ophiuroidea 4 the organs are not prolonged from the disk into the arms, consequently
FIG. 184. — Amphlura squamata. One of the Ophiuridae. Nat. size.
Photo, by W. H. C. P.
the arms may be thrown off without injury to the animal ; hence the name "brittle-star." The brittle-stars fall into two groups, in one of which, the serpent-stars, the arms are uiibranched, while in the other, the "basket- fish," the arms are branched.
Of the serpent-stars there are two common forms on the New England coast,- -a Avhite species, with long, slender arms, Amphiurab squamata 6 (Fig. 184), and the spotted Ophiopholis,7 which has shorter, stouter arms. The
1 Blood-red. 5 dfjL<pl< round about ; ovpd, tail.
2 sol, sun ; aster, star. 6 Scaled (squama, a scale). 8 ej>5e/ca, eleven. 7 60is, snake ; 0oXi':, scale.
4 50ts, serpent ; ovpd, tail.
THE STARFISH AXD ITS ALLIES
199
animals live in crevices of the rock, and being of rather small size, are not commonly seen. At the base of the arms, on the right and left, are a pair of slits, which form the exits from pouches into which the reproductive glands open. In certain species the pouches are used for brood- ing the young. The basket-fish occur in Northeastern
FKJ. 185. — Strongylocentrotus, the Eastern green sea-urchin, with tube feet extended. From " Standard Natural History."
waters, from low tide to one hundred fathoms, and are often brought up by fishermen, to whose lines they have a habit of clinging. The branching of the arms enables the animal to hold its prey, which consists of shrimp and fish. The Echinoids, or sea-urchins, may be regarded as star- fishes in which the arms have shortened and the disk en- larged so as to fill up the interspaces, and make a solid,
200
ZOOLOGY
nearly spherical form. The sea-urchins eat various small animals, and get food also from small bits of organic matter in the mud which they swallow. They live more concealed than the starfish, for some burrow in the mud and others -such as our green sea-urchin of the Maine coast (Fig. 185) — grind out pockets in the rocks by means of their spines. Others cover themselves with seaweed, and thus become inconspicuous. Besides the green sea-urchin,
FIG. 186. — Arbacia, the Easteru black sea-urchin. Tube feet retracted. Nat.
size. Photo, by W. H. C. P.
which is found north of Cape Cod, we have a black sea- urchin (Arbacia, Fig. 186), which extends south as far as North Carolina. We have on the east coast also two kinds of flat sea-urchins (sand-dollars), which live in the sand from low water to one hundred fathoms. Their spines are small and silky (Fig. 187). Some sea-urchins lose their strictly radial form and become bilateral, having a ] jointed anterior end (Fig. 188).
THE STARFISH AND JT-S ALLIES
201
The Holothurians l may be likened to soft-skinned sea- urchins, with the body drawn out to the form of a cucum-
FIG. 187. — Echinarachnius par ma, the sand dollar. Spines removed from left side. Nat. size. Photo, by W. H. C. P.
FIG. 188. — Clypeaster, a bi- lateral sea-urchin from the West Indies. Spines partially removed and surface rubbed in patches. Reduced photo.
ber, or even of a worm. The calcareous skeleton is reduced to small plates embedded in the skin. The mouth is sur- rounded by a circle of tentacles. The ambulacral feet are sometimes absent. The Holothurians live in sand and mud, often deeply buried, and feed on small marine animals or the decaying particles mingled with the mud which they devour. They are of considerable economic importance. The members of one genus (Holothuria) is taken in great numbers on the coral reefs of the Pacific
i v\o6ovpioi', a sort of water-polyp.
FIG. 189. — Caudina, the tailed Holothuriau. a, mouth; b, anus. After Selenka.
£02
ZOOLOGY
J
FIG.
191. — Metacrinus interruptus.
After P. H. Carpenter.
FIG . 15 10. — »S'// » apt a inhe re tt s. a , tentacles; b, longitudinal mus- cles; c, alimentary tract. - After Quatrefages.
Ocean and the China Sea, where they are com- monly known as lk tre- pangs." They are cut open, washed, boiled, dried, and sometimes smoked. They are sold in Chinese ports, and some species are con- sidered by Chinese epi- cureans as great deli- cacies. Several species of Holothurians occur on the Maine coast. A bar- rel-shaped form with a
APPENDIX TO CHAPTER XIII 203
sort of tail (Caudina,1 Fig. 189) occurs on the Massa- chusetts coast. A worm-like form, but with a beautifully transparent skin (Synapta,2 Fig. 190), is found in sandy beaches from Massachusetts to New Jersey.
The Crinoids,3 or sea-lilies, are familiar as fossils to resi- dents of New York State and the Ohio and Mississippi valleys. The living animals are less often seen, for they are inhabitants of the deep sea. They have a cup-like body, with the mouth at its centre directed upward, and surrounded by tentacles (Fig. 191). The cup is either borne on the end of a long stalk or is unstalked. The former condition is more usual among the fossil species.
APPENDIX TO CHAPTER XIII
KKY TO THE PRINCIPAL CLASSES OF ECHINODEKMATA
«i. Sessile ; mouth turned upward ; body calyx-shaped Crinnidea
(Sea-lilies)
a-2- Not sessile.
b\. Body short ; skin hard, containing calcareous plates ; mouth directed downward ; madre- poric plate present.
Ci. Body with arms which carry a longitu- dinal series of plates.
di. Arms with ventral furrow . . Axtcrnidea
(Starfish) d2. Arms without ventral furrow . . Ophiuroidea
(Serpent stars)
1 cauda, tail.
2 awairrbs, fastened together ; from vvv, with, and ctTrrw, to fasten.
3 Kpivov, lily ; dSos, form.
204 ZOOLOGY
c%. Body without arms ; more or less spheri- cal or cake-shaped .... Echinoidea
(Sea-urchins)
62. Body elongated ; skin soft, leathery, contain- ing microscopic calcareous bodies ; madre- poric plate absent ; mouth surrounded by
tentacles Holothuroidea
(Sea-cucuuibers)
CHAPTER XIV
THE HYDRA AND ITS ALLIES
HYDRA belongs to the group of Coelenterata,1 which includes sponges, and certain organisms with nettling capsules — Cnidaria.2 The Coelenterata have a more or less radial form, and a system of internal cavities serving for digestion as well as for body cavity.
The sponges are all sessile, have no nettling capsules, have the body wall perforated by many fine incurrent openings, and a larger exhalant opening (Fig. 192).
The Cnidaria3 have nettling organs of some sort. Hydra belongs to this group.
There are two common species of Hydra ; the one is of a green color {Hydra* viridis5)^ and the other is flesh- colored {If. fuscaQ~). They are found in standing or slow- running water, attached to submerged plants, sticks, and stones. Throughout the winter they live at the bottom of ponds, below the ice. The body of Hydra is soft and highly contractile, so that, when first drawn from the water, it appears like a speck of jelly. Left undisturbed, the animal expands, and its five to eight tentacles wave
s, hollow; evrepov, intestine. nettle.
3 A key to the principal subdivisions of the Cnidaria and especially of the Hydromedusse will be found in the Appendix to this Chapter.
4 vdpa, a mythological monster, capable of regenerating its head.
5 Green. 6 Brown.
205
206
ZOOLOGY
slowly about in search of food. The tentacles are richly supplied with nettling cells, each of which contains a fluid-filled capsule, in which is coiled a thread-like tube.
FIG. 102. — Sycon gelatinosum. A portion slightly magnified: one cylinder (that to the right) bisected longitudinally to show the central stomach cavity opening on the exterior by the osculum, and the position of the incur- rent and radial canals; the former indicated by the black bands, the latter dotted, ip marks the position of three of the groups of inhalant pores at the outer ends of the incurrent canals ; o, osculum.
When stimulated by contact with some foreign body the tentacle closes around it, while from each capsule the lasso-thread rolls out as the finger of a glove is rolled inside out, and discharges the irritating poison .through
THE HYDRA AND ITS ALLIES
207
the lumen of the thread. If a small animal has been the irritant, it is instantly caught in the thread, paralyzed by the poison, and soon conveyed to the Hydra's mouth. The principal food of Hydra is small worms and the smaller Crustacea, such as Daphnia and Cyclops.
a
\ fWo/ ')
v) Ik
FIG. 193. — A colony of Cordylophora lacustris, on a shell of Mytilus. For clearness, a number of the erect branches are cut off at the stolon, a, very young shoot without lateral branches; b, young stock with lateral branches but no gouophores; c, a stock with gonophores on lateral branches; d, fully grown stock with lateral stems. After Schulze.
Fresh-water Cnidaria are of extremely few kinds. Hydra was once regarded as the only instance, but others are now known. One of these, called Cordylo- phora, is found chiefly in brackish water or in fresh water, near the coast. Like many of the marine hydroids, Cordy-
208 ZOOLOGY
lopliora produces its young in special capsules, called gonophpres, which are rudimentary jelly-fishes (Fig. 193). The young become free when they have gained an elon- gated, cylindrical form. There are other fresh-water species which have free jelly-fishes. In this country we have a species, Microhydra l Ryderi, hitherto known only about Philadelphia, whose hydroid stage is extremely small and bears no tentacles. The jelly-fishes are set free during July. Fresh-water jelly-fishes have also been described from Lake Tanganyka, Africa, and from a tank at Regent's Park, London, to which they had doubtless been imported on plants. It is very probable that all fresh-water hydroids which produce jelly-fish have, geo- logically speaking, recently come from the sea. Hydra, however, is probably a long-established fresh-water species.
The marine hydroids are, in contrast to the fresh- water ones, very numerous. The Hydrocorallidae 2 are peculiar in that they secrete a great amount of calcareous sub- stance, so that they were formerly regarded as belonging to the typical corals (Scyphozoa). They may be easily distinguished by the absence of radial septae in the cups occupied by the hydroid. Here belong the millepore corals of Florida.
The Tubularidae3 include some hydroids of large size, single individuals of Tubularia becoming six inches long. Other species grow 011 gastropod shells which are occu- pied by hermit-crabs (Figs. 194 and 195). So thickly do they grow that they make a plush-like covering on the upper part of the shell, and they have the curious habit
1 Small Hydra.
2 Combining the qualities of Hydra and the corals.
3 From tubulus, a little tube.
THE HYDRA AND TTN ALLIES
209
of building out the lip of the shell so as to enlarge the aperture. They do this in order that the hermit-crab, as it grows larger, shall not be forced to exchange the shell for a larger one, leaving the hydroids on the cast-off shell to roll about on the beach and perish.
Of the Campanularidae,1 or bell-hydroids, one of the common representatives is Obelia,2 which may be found at low tide hanging from
-i i ,1 11 FIG. 1!H. — Stylactis, a tubularian
rocks beneath seaweed, and hydroid> gl.0^ugou asn:iiL Nat.
looking like delicate white size. Photo, of living animal by
threads (Fig. 196). Observed
FIG. 195. — Hydractinia, a tubularian hydroid. a, colony growing on gastro- pod shell inhabited by a hermit-crab ; b, bit of colony enlarged ; dz, modified, tactile, individuals; s, reproductive individuals; sp, spines. From Parker and Haswell.
campanula, a little bell.
os, a spit.
210
ZOOLOGY
under the microscope each stem appears as a series of hydranths placed in zigzag1 fashion, one beyond the other.
FIG. 10(!. — Obelia ( ?) , a group of campanularian hydroid colonies. Nat. size.
Photo, by W. H. C. P."
Another common kind is Sertularia,1 which forms rusty brown threads (Fig. 197 ). All the hydranths of one stem
occur in one plane and oppositely.
Both t u 1) 11 1 a r i a 11 and c a m p a 11 u 1 a r i a 11 hy droids may give rise to jelly-fishes. These jelly-fishes are formed as buds on the hydrant] i, and after they become able to
move of themselves they are ;. 1<»7. — Sertularia, a small colony. J
i.r> nat, size. cut off from the parent and
1 Derived from serta, garland.
THE HYDRA AND J7'N ALLIES
211
swim away. The jelly-fishes then give rise to the sexual products and discharge them into the water (Fig. 198). In other cases the jelly-fish is formed but never separated
FIG. 198. — Bougainvillea ramosa. A, entire colony, natural size; B, portion of the same magnified; C, immature medusa; dr. c, circular canal; cu, cuticle or perisarc ; ent. ccw, enteric cavity ; hyd, polyp or hydranth; hyp, hypostome or manubrium ; med, medusa; mnb, manubrium ; rad. c, radial canal; t, tentacle; v, velum. From Parker's "Biology," after Allman. This is closely allied to the New England B. super cllians.
212
ZOOLOGY
from the parent, and the eggs develop in the bud. In still other cases a mere bud, called gonophore, is formed, which becomes full of sexual products without ever ac- quiring resemblance to a jelly-fish. The jelly-fish is the primitive type which has undergone a reduction in some cases to a gonophore. It is an interesting fact that in certain species sometimes jelly-fishes and sometimes gono- phores will be produced. In the Campanularidae the
FIG. 199. — Zygodactyla. Reduced. From a drawing by A. Ajjassiz.
gonophores are encased in a cuticular capsule, but in the Tubularidse they are quite naked.
There are certain hydromedusre in which the hydroid stage is unknown or known to be lacking. Here belong some jelly-fishes of large size, like Zygodactyla, one of the Trachomedusse of our coast, which may become eight to ten inches in diameter (Fig. 199). Besides these the sea contains many small species, which are easily captured in the net, and which are of extreme beauty and delicacy.
Besides the Hydromedusre, the group of Hydrozoa in- cludes the Siphonophora.1 These animals are always colonial and free-swimming, and are among the most
1 0-/0WJ/, a siphon ; </>o/)6s, bearing.
THE HYDRA AND ITS ALLIES
213
beautiful inhabitants of the sea. Those who have crossed the Atlantic are acquainted with the " Portuguese man-of-
•fon.
FIG. 200. — Physalia arethusa. Nat. size. After Agassiz.
•net
nlc
FIG. 201. — Halistemma terge- stinum. The entire colony. cw, coenosarc; dz, dactylo- zooid ; hph, hydrophyllium or
bract; net, nectocalyx or swimming-bell; ntc, battery of nematocysts; p, polyp; pn, pneumatophore or float; t, tentacle. After Glaus.
214 ZOOLOGY
warv (Physalia,1 Fig. 192), which often swarms in the Gulf Stream. The huge float which lies on the surface of the water serves also as a sail by which the animal is transported by the wind. There are other smaller, more graceful species of more typical form (Fig. 201). The structure of a siphonophore is very complex. From the float hangs a central stem. Upon this stem are budded feeding zooids — hydranth-like forms provided with mouth and tentacles — and reproductive zooids- - gonophore-like forms which produce the germ cells. There are leaf -like expansions also, which are rudimentary medusae. All the many forms budded on the stem are modifications of the hydroid type.
Contrasted with the Hydrozoa are the Scyphozoa,2 which are, on the whole, larger animals. These, too, occur both in the sessile, polyp form and in the jelly-fish form. The sea-anemones are common examples of the polyp. These are, for the most part, solitary, fleshy creatures, often brilliantly colored, and therefore appropriately called by the Germans " sea-roses," and in this country and in Eng- land " sea-anemones." They are of cylindrical form, bear a circle of tentacles around the mouth at the upper end, and have a muscular base by which they attach themselves. They vary in diameter from one-sixth of an inch to two feet. Some species live in the sand, out of which they get some organic food, and at least one species (Minyass) is free-swim m ing.
Our commonest Northern sea-anemone is Metridium marginatum (Fig. 202), which occurs on rocky shores south
bladder. 2 o-Kixpos, cup ; fwoz>, animal.
3 For a figure of Mnyas, see Parker and Haswell, "Text-book of Zoology," p. 189, Fig. 13U.
THE HYDRA AND ITS ALLIES
215
to New Jersey, but reaches its maximum development along the coast of Maine. It varies greatly in color, some individuals being white, others salmon-colored or olive. The flat upper surface bears the slit-like opening to the internal sac. Either one or both angles of this slit have thickened edges, and corresponding to this difference is a
FIG. 202. — Metridium, one of our sea-anemones. Two individuals shown expanded. Photo, of the living animals in the water, by W. H. C. P.
difference in the internal structure. Inside, the central cavity is separated into compartments by radial partitions. The coral polyp does not differ essentially from Metri- clium. But it has the habit of secreting lime at its base, so that, in course of time, a high cup is built up. The top of the cup bears radial septa,1 which are laid down
i Fig. 203.
216
ZOOLOGY
in the interspaces between the fleshy partitions men- tioned in speaking of Metridium. Since most corals, like
FIG. 203. — Coral cup of manicina. Nat. size. Photo, by W. H. C. P.
hvdroicls, bud freely, and since every bud secretes coral at its base, an extensive and complicated limy mass may be produced. This is the way in which the brain corals and
•6£tt***-.fi-i-^ •*.•>. ,- ,
FIG. 204. — Astranyla d<i)ite,a. cluster of our Northern coral-polyps, resting on limy bases of their own secretion. The animals are extremely delicate and transparent. From a lithograph by Louis Agassiz's artist Sonrel.
branching corals are formed. The only coral of the north- eastern United States is Astrangia dance, which occurs north to Cape Cod. It is a beautifully transparent species, and forms thin encrustations of limy matter (Fig. 204).
THE HYDE A AND ITS ALLIES 217
Coral reefs are almost exclusively the product of coral polyps modified by the environmental conditions. The reef-building corals live in shallow water from low-water mark to a depth of one hundred feet only. Their dis- tribution along the coast line depends upon the winter temperature of the sea, since they cannot live at a tem- perature below 20° C. ; consequently reef -building corals are confined to warm latitudes. However, tropical shores which are washed by arctic currents, such as the west coasts of Africa and South America, are destitute of coral formations. On the other hand, shores in the temperate zone that are washed by tropical currents, such as our Florida coast which is washed by the Gulf Stream, may be rich in coral reefs. Corals demand undiluted sea-water, hence they do not thrive in harbors which receive the waters of great rivers --a circumstance of great impor- tance for the commerce of tropical countries. Moreover, corals require a rock bottom on which to build, and they cannot gain a foothold on shores where the cliffs descend precipitously to great depths. Coral reefs receive dif- ferent names according to their varying relations to the shore. Fringing reefs are found close to the shore line. Barrier reefs lie at some distance from land, with a body of quiet water between them and the shore. An Atoll is a further step, in which a small island, formerly sur- rounded by a barrier reef, has disappeared, leaving a cir- cular reef surrounding a body of water (Fig. 205). Exactly how the central land disappears, whether by sub- sidence of the sea floor as the reef grows up or by being washed away, is still it matter of dispute.
Budding and the Formation of Colonies. The Cnidaria are one of three groups of animals which have the habit of
218 ZOOLOGY
forming colonies by budding, somewhat after the fashion of plants. The other groups are the Bryozoa, or " sea- mats," and the Tunicata, or " sea-squirts." In all cases the buds arise from a definite part of the parent body and develop into a definite form, often exactly like that pro- duced from the egg. When the buds remain attached to the parent, a compound individual or colony is produced. These colonies differ greatly in form. Thus among hy- droids we have colonies which produce runners, from which alone, and not from other hydranths, new hydranths arise.
FIG. 205. — Atoll iii Fiji Islands (Nanuku Levu). The large circle of white made by breakers indicates the position of the coral reef. A small bit of land still remains in the interior lagoon. Photo, by Dr. "W. McM. Wood- worth. From A. Agassiz, " Coral Reefs of Fiji."
In another case (< )belia), one hydroid buds from the side of another and rises beyond it, continuing the main stem of the colony. Since its descendants do the same, the stalk is made up of successive generations of hydranths. Some- times the hydranths are placed close together and oppo- site, like the leaves of Arbor vitte (Sertularia, Fig. 197). Again, there may be a main stalk composed of one hy- clranth and a series of lateral branches in one plane, mak- ing a fan-like arrangement of the colony. Or the lateral
£5 *~
branches may arise in any plane, producing a bushy colony.
THE HYDRA AND ITS ALLIES
219
The variety in the form of the colony possessed even by a single species adds to the diversity of hydroids.
The Ctenophora, or sea-walnuts, are a small group of exclusively marine organisms which float on the surface of the sea, and like most animals having this habit have become clear as glass. Many of them are highly phos- phorescent (Fig. 206).
In any colony a division of labor may occur among the constituent individuals, or zooids. Thus in the simplest cases we have crawling zooids, or stolons, and feeding zooids. In Hydractinia1 we have, in addi- tion, reproductive zooids, nettling zooids, and passive, thorn-like zooids. Here we see how com- pletely subservient the individual is to the good of the community. This subserviency has ruled in all successful colonies of animals.
Regeneration. — Closely allied to the power of budding is that of reproducing a lost organ. Suppos- ing the " head ' (mouth and ten- tacles) of a Hydra to be cut off, the
base will reproduce the lost head. Suppose the base to be removed, the head will reproduce a new base. When a Hydra is cut in two transversely, two Hydras result where formerly there was only one. Even three or more Hydras may arise when a Hydra has been cut into so many pieces. Where other conditions are favorable to life, you can hardly kill a Hydra by mutilation. A trace of this
i Fig. 195.
FIG. 206. — Idylia, a sea- walnut, seen from the broad side. Half nat. size. «, anal opening ; b, lateral tube; c, circulai- tube ; d,<', f, g, ft, rows of paddles. After Agassi/.
220
ZOOLOGY
capacity for regeneration, as it is called, is seen also in man when a wound heals, and a diseased organ, even when partly destroyed, is made whole again.
APPENDIX TO CHAPTER XIV
KEY TO THE PRINCIPAL SUBDIVISIONS OF THE CNIDAKIA
a\. Body composed of 4, 6, or many rays ; nettling
organs well developed. b\. Mouth at apex of an oval cone ; cavity
simple Class
c\. Existing for the most part in 2 forms ; a sessile one, hydroid ; and a free- swimming one, medusa. The hydroid form is sessile ; the medusae are mostly small, or may remain at- tached to the hydroid . Order c2. Free-swimming colonies composed of hydroid and medusoid individuals budded on a floating stem . Order
62- Mouth at bottom of an oral crater ; cavity di- vided by radial partitions. The more com- mon forms are large jelly-fishes . Class «2. Body composed of 2 radii, with 8 meridional rows of plates of cilia ; nettling capsules modi- fied to form adhesive organs . . Class
Hydrozoa
Hydromedusce
Siphonophora
(Portuguese man- of-war, etc.)
Scyphozoa
Ctenophora
(Sea-walnuts)
KEY TO THE FAMILIES OF THE HYDKOMEDUS.E
«i. Hydroid individuals, without cuticula or stolons ; fresh water .
«2- Hydroid individuals, if present, with cuticula or stolons; marine.
Hydroidw
(Ex. Hydra)
APPENDIX TO CHAPTER XIV 221
61. Hydroids present ; medusae without free
auditory clubs.
Ci. Hydroid stocks, with calcareous ex- ternal skeleton ; no free medusae . Hydrocorallidce Co. Hydroid heads never enclosed in cuticu- lar cup ; medusae, if free, without marginal vesicles ; gonads on manu- brium ...... Tubularities
c3. Hydroid heads enclosed in calyx ; me- dusae, if free, with gonads on radial
canals Campanularidce
b-2- Hydroids absent ; medusae with free-stand- ing auditory clubs.
GI. Gonads on radial canals . . . Trachomedusas Cz- Gonads on manubrium . . . Narcomedusas
CHAPTER XV
THE PARAMECIUM AND ITS ALLIES
PARAMECIUM l belongs to the Protozoa,2 the lowest group of animals, characterized by the fact that the body contains no specialized tissues and organs, but is made up of a single cell, and is usually microscopic. Protozoa live in water or in moist situations.3
The Infusoria were unknown to man until the latter half of the seventeenth century, when a Dutch naturalist named Leeuwenhoek, by means of the newly invented compound microscope, studied and described several kinds which he had found in standing water and called animal- cuke or water insects. As the microscope became per- fected, progress was made in the study of these organisms, but even in the early half of our century several eminent zoologists maintained that the Infusoria possessed digestive, neural, hamial, and reproductive organs. The proper structure of the Infusoria has been generally recognized only within the last fifty years.
The conceptions formerly entertained concerning the origin of Infusoria were as erroneous as those relating to their internal structure. These erroneous conceptions were an inheritance from a time when even scientific men
somewhat long.
2 -rrpwTos, earliest ; faov, animal.
3 Keys to the four classes of Protozoa and to the orders of Infusoria will be found in the Appendix to this Chapter, page 229.
222
THE PAliAMECIUM AND ITS ALLIES 223
held that many of the larger animals, such as eels, bees, and flies, were generated without parents. This was the theory of "'spontaneous generation/' In time this theory became much more restricted. It was found that the maggots in putrid meat are not generated " spontaneously' out of the meat, but are derived from flies' eggs, and, in their turn, develop into fertile flies. But the idea that Infusoria are formed out of inorganic material continued to be held until much more recently, until Pasteur, Tyn- dall, and others demonstrated that fluids heated to a sufficiently high temperature for a sufficient time, and then, while hot, sealed from contact with air, do not develop Infusoria, no matter how long they may be kept. This method of excluding Infusoria and other minute organisms, especially bacteria, is employed to-day in can- ning meat, vegetables, and fruit. The experiments re- ferred to gave a death-blow to the theory of spontaneous generation, and led to the conclusion that all Infusoria are derived from living germs.
Whence the living germs come which enter the water it is not difficult to determine. Many Infusoria can pass into a quiescent "spore" stage in which they may be dried and blown about without loss of life. Dry grass, straw, and other substances contain some of the germs, and others float in the air and fall as dust into the water. Even drinking water may contain here and there an infusorian or its germ. When, therefore, one fills a clean vessel with pure water, and puts hay or dry leaves in it, and lets it stand open to the air in a warm place, the result is pretty sure to be that germs develop in the mixture. The heat and the organic infusion merely facilitate this development.
224
ZOOLOGY
Of all the Infusoria, none is more abundant than Para- mecium. It occurs everywhere, principally in stagnant fresh water, but also in salt water. It lives entirely on vegetable food, and is sure to abound wherever plant matter is undergoing decay. When a culture is once
FIG. 207. — Carchesium, a stalked Vorticella. Greatly magnified.
photograph of the living animals.
From a
started from a hay infusion, — which takes one or two weeks, — it will be found to thrive especially on corn-meal. As an example of the Heterotricha, Stentor,1 the trumpet- animalcule, may be mentioned. Stentor is found attached to vegetable debris — sticks, stones, water-weeds, and other objects — occurring in pools, ponds, lakes, and sluggish streams. These things should be gathered and placed in
1 ST<?I>TO>/>, a Greek at Troy, known for his loud voice.
THE PAEAMECIUM AND ITS ALLIES 225
an aquarium, when the Stentors, if present, will attach themselves to the glass sides of the vessel. The attach- ment of Stentor to objects is not permanent, for it may loose its hold and swim free. When the animal is stained in hcematoxylin, the characteristic nucleus, looking like a chain of beads, becomes evident.
Vorticella,1 the bell-animalcule, is found in pools or infusions, permanently attached by a long stalk. When the animal is irritated, it contracts its stalk, which twists into a close spiral. Carchesium 2 differs from Vorticella, in forming colonies, so that a number of heads are attached to a central stalk. A colony, when fully expanded, appears like a fine, white mould attached to a submerged object. In both of these types the food consists of small organic particles, which are swept into the gullet by the circlet of cilia placed around the upper end of the body.
The Suctoria3 are sessile Infusoria, from whose upper surface numerous remarkable sucking-tentacles arise. By means of these tentacles the animal can hold on to Para- , mecia and other free-swimming Infusoria, from which it extracts the body fluids. Some Suctoria are stalked (e.g. Podopliora^, while others are unstalked (e.g. Aeineta'0). They are found most abundantly in standing water, either fresh or salt, and are often attached to other animals, - Bryozoa, entomostracans, and pulmonate mollusks.
Of the group Flagellata,6 or lash-animalcules, Euglena7 is a common representative . It is of microscopic size, but occurs in such numbers as often to give a decided green
1 Dim. from vortex, whirlpool. 4 TTOUS, foot ; 60/>tfs, eyebrow.
2 Kapxyviov, goblet, Fig. 207. 5 d/aVr/Tos, without movement.
3 From sugere, snctum, to suck. & JlayeUum, a lash.
7 evy\r)vos, with a beautiful eye.
226
ZOOLOGY
color to the pools of water it inhabits. It is spindle- shaped, and bears a flagellum at its anterior end. At the base of the flagellum is a red "eyespot."
Allied to Euglena is Volvox,1 a spherical, multicellular
c-.vac
FIG. 2<>S. — Eiif/lena viriilis, a lash-animalcule. A-D, four views illustrating the characteristic movements ; E and //, enlarged views of adult ; F, out- line of anterior end further enlarged ; G, resting stage ; cy, cyst ; .//, liagel- huu ; m, mouth; nu, nucleus; w, gullet; pg, pigment spot; /•, reservoir. After Kent and Klebs.
~~| organism, half animal and half plant, and forming a sort of con- necting link between the Pro- tozoa (or one-celled animals) and the multicellular higher organ- isms. Volvox occurs abundantly in our ponds and gets its name from its manner of revolving in
FIG. 209. -- Volvox globator. t]ie water (Fig. 209). Much magnified. Photo. Y, .'••.•••. £
of the living animal. Very different in habitat irom
1 From volvere, to roll.
THE PAEAMECIUM AND ITS ALLIES 227
the foregoing are the Sporozoa,1 which are minute rod- like organisms, occurring as parasites in the body of various kinds of higher animals, especially in the food- tract. They increase by transverse division of their rod- like bodies ; but periodically they encyst, and divide into numerous "spores," which, under favorable conditions, are set free in great numbers.
\ *': ;/?SiVr.Ar? ''
-
Jiiii; fv
(^?iii^m^m0^^n
~- ^-iSSfS?;0;|Sssk
FIG. 210. — Amoeba, the proteus animalcule. Greatly magnified, n, the nucleus; w. v, water vacuoles ; c. ?-', contractile vacuoles; /. v, food vacuoles. E. B. Wilson, "The Cell."
Of all Protozoa, probably the simplest is Amoeba.2 This type varies greatly in size, from 0.02 mm. to about 0.3 mm. It appears as a clear, highly refractive body of changing outline. The body does not look homogeneous when viewed with a high power, but contains various granules derived from ingested food, vacuoles of water, and a trans- parent, slightly more dense, spherical or ellipsoidal body,
1 0-7T6/OOS, spore ; fwoj/, animal.
2 aioi3? alteration.
228 ZOOLOGY
the nucleus, which it is often difficult to make out on the living animal. The whole substance of the Amoeba is mobile, so that the internal organs have no fixed relation to one another. Quantities of Amoeba can usually be obtained for study by gathering the mud from the edges of stagnant pools, or by scraping the green growth from flower-pots, and letting these gatherings, covered with a little water, stand in a fairly warm place for two or three weeks.
Even the Protozoa bear important relations to man. One species, Amoeba coli, has long been known occasion- ally to inhabit the food canal of man, and it is now known that an amcebiform organism (probably one of the Sporo- zoa) is the cause of malarial diseases. Since in one common species 48 hours are required to complete a developmental cycle, the recurrence of the fever every alternate day is explained. It is now demonstrated that at least one of the common agents in infection with malaria is the mosquito, which carries the germs of the malaria parasite from one host to another. Other Sporozoa, of at least one species, are parasitic in the human liver, others attack fish and cause them to die in large numbers; still others cause sickness and death among domesticated animals. The Texas fever among cattle is believed to be caused by an organism l belonging to this group, the inoculation of the cattle being effected by the cattle-tick.
The reproductive capacity of Protozoa is so great that their importance in the world, despite their small size, is not astonishing. One of the early students of Protozoa, Ehrenberg, computed that from one individual of Para- mecium aurelia 268,000,000 might be developed in one
1 Called Piroplasma biyauinum.
APPENDIX TO CHAPTER XV 229
month by the process of division. Apparently the divi- sion cannot go on indefinitely, but from time to time the Paramecia unite temporarily in pairs and undergo an exchange of some of their nuclear matter. This is doubt- less the beginning of what is known in the higher animals as sexual reproduction.
APPENDIX TO CHAPTER XV
KEY TO THE FOUR CLASSES OF PROTOZOA
a\. Without non-retractile appendages.
bi. With retractile pseudopodia .... Rhizopoda
(Ex. Amoeba)
62. Without pseudopodia ; covered with an im-
perforate cuticula ; parasites . . . Sporozoa «2. With non-retractile appendages.
61. No cilia, but with one or more flagella . . Flagellata
(Ex. Euglena)
62. With cilia, or sucking tentacles . . . Infusoria
(Ex. Paramecium)
KEY TO THE SUBCLASSES AND ORDERS OF INFUSORIA
a\. With vibratile cilia and no sucking tentacles . CILIATA
b\. Body everywhere closely beset with cilia.
GI. No adoral zone Holotricha
(Ex. Parameciuiu)
C2. Adoral zone present .... Heterotricha
(Ex. Stentor)
62. Body only partly ciliated.
GI. Cilia limited to ventral side . . . HypotriGha c2. Cilia form a circlet around or at upper
edge of animal Peritricha
(Ex. Yorticella)
a2. With sucking tentacles . . ... SUCTORIA
CHAPTER XVI
THE SMELT AND ITS ALLIES
THE smelt is one of the class of fishes.1 This class com- prises vertebrates that breathe by means of gills and do not use their appendages for walking.
The smelts, which belong to the salmon family, are pre- eminently inhabitants of the northern temperate zone, since all but one of the ten genera occur only there. They are small marine fishes, and although a feAv are inhabitants of the deep sea, most live near the shore, and in the spring ascend rivers to spawn. Some of them have become cut off from descending to the sea and live permanently, as tk land-locked " forms, in fresh water. Such " land-locked ' individuals are of smaller size than the marine ones. The food of smelts, like that of other Salmonidee, is chiefly animal, consisting of smaller fishes or insects, small crusta- ceans, and mollusks.
Smelt are of considerable economic importance, since they share with other members of the salmon family a delicately flavored flesh. Our Atlantic form, Osmerus 2 mordaxf which ranges from Delaware Bay northward, is caught most abundantly in Maine. The total Atlantic
1 Keys to the principal orders of fishes and the six suborders of the Teleostei will be found at the end of this Chapter, page 252.
2 6o-/>o7p6s, odorous ; the Greek name is the equivalent of the English "smelt." 3 Biting.
230
THE SMELT AND ITS ALLIES 231
smelt fishery is valued at 1125,000. Smelt eggs are arti- ficially hatched and planted in rivers previously unin- habited by them. Smelt are said to return to these rivers after spending the winter in the sea. The early settlers on our Eastern coast, like the Indians before them, used smelt to fertilize the land. At present this wasteful pro- ceeding is illegal ; but the bones and scraps from the canning factories are used to make commercial fertilizers, since they are rich in phosphorus — an important plant food.
The family Salmonidae includes some of our most im- portant food fishes. It is distinguished from other fami- lies of Physostomi by the circumstances that both ventral and adipose fins are present, that both premaxilla and maxilla bear teeth l and form the margin of the upper jaw, and that the head is naked, body scaly, belly rounded, and pseudobranchue present. Besides the smelt there are numerous important species. The salmon proper2 are restricted to the north temperate and arctic regions, and live either in the sea, migrating to fresh water to spawn, or exclusively in brooks and lakes. The migrations of salmon from the sea up the rivers are remarkable. Hun- dreds of miles are sometimes journeyed, rapids swum, and falls leaped, for the purpose of laying eggs in some remote lake. The females, with their burden of eggs, have be- come so exhausted at the end of the migration that most, or all of them, die immediately after laying the eggs. On the Atlantic coast the Penobscot River has the most im- portant run of salmon. The Pacific salmon passes up the Sacramento and Columbia rivers, and up many rivers of British Columbia and Alaska. In these rivers the fish
211. 2Fig. 212.
232
ZOOLOGY
are caught as they ascend to breed. Such is the greedi- ness and lack of foresight of the canning fisheries on the
Columbia River that very few salmon are permitted to pass the nets of the canning factories, and consequently
THE SMELT ANT) ITS ALLIES
233
the apparently inexhaustible supply of this fish lias been immensely reduced, and the fishery will soon become destroyed.
op
FIG. 212. — Salmofario. ct. I, adipose lube of pelvic fin ; an, anus ; c./, caudal fin ; d. /. 1, first dorsal ; d.f. ?, second dorsal or adipose fin : I. /, lateral line ; op, operculum; pct.f, pectoral fin; pv.f, pelvic fin; v.f, ventral fin. After Jardine.
The trout, of which there are a number of kinds on both continents, is commercially much less important than the
FIG. 213. — Coregonus, the lake whitefish. Much reduced. From Goode.
salmon proper. As a result of overfishing, and the pollu- tion of streams by factories and sewage, this fish is dis- appearing from Eastern waters.
ZOOLOGY
The whitefish (Coregonus1), of which we possess many species, is exclusively an inhabitant of fresh water.2 Its teeth are almost completely absent, or very small ; it feeds almost exclusively upon small arthropods and mollusks. It is of very great commercial importance, its fisheries being valued tit nearly three million dollars a year.
Leaving now the Salmonidse, we may briefly consider some of the other more important families of bony fishes.
FK;. 21-4. — Morone americana, the white perch. The fish is searching for food along the bottom of the aquarium, an instinct which it shows in nature also. About one-third nat. size. Photo, of living animal by Dr. R. W. Shufeldt, from " Bull. U. S. Fish Com.," 1899.
The darters are spiny-rayed fishes of small size, from four to seventeen centimetres long, brightly colored, and with well-developed pectoral fins. They live in clear streams, half concealed under stones, and are most abundant in the Mississippi drainage basin.
, the pupil of the eye ; ywvia, angle.
2Fig. 213.
THE SMELT AND ITS ALLIES
235
The perches are a widespread family, represented in this country chiefly by the common yellow perch of the East, the u wall-eyed pike ' ' of the Great Lake region, and the white perch of the Atlantic coast (Fig. 214). These fish have an oblong, compressed body covered with small scales ; they are highly rapacious, and are believed to be
FIG. 215. — Eupomatis yibbosus, the common sunfish. Two-thirds uat. size. Photo, of living animal by Dr. R. W. Slmfeldt, "Bull. U. 8. Fish Com.,"
1899.
destructive to the young of other species of fish. They are esteemed as food, although fortunately not to the extent of annihilation.
The sunfishes1 have a percoid form, but have only one dorsal rln instead of two. They live in fresh water, have
1 Fio-. 215.
236
ZOOLOGY
rapacious habits, are brilliantly colored, and build nests in the sand, which both male and female watch over and
defend with courage. Some species living in the Great Lakes are known as black bass or rock bass. The small New England species, with the brilliant red edge to the operculum, is called pumpkin-seed.
The toadfishes (Fig. 216) are represented in our faunas by a common species which lives under stones in harbors and attaches its eggs to the under side of stones. It is a vigorous fighter.
The sculpin (Fig. 217) is closely related to the toadfish. Like the latter it has a broad head and nearly scaleless body. The pectorals are large, and the two dorsals extend along the greater part of the back. Allied to the foregoing is the rock eel (Fig. 218), which is sometimes brought up in the seine from a depth of 8 to 10 fathoms.
FIG. 216. — Batrachus tau, the toadfish. Dorsal view. Two-thirds nat. size. Photo, by W. H. C. P.
FIG. 217. — Acanthocottns, the little sculpin. Two-thirds nat. size. Photo.
by AV. H. C. P.
The silversides are especially abundant along our At- lantic coast. They have an elongated, somewhat com-
THE SMELT AND ITS ALLIES
237
pressed body, and a broad, bright silvery band on the sides, against a greenish general body color. The dorsal
x. : •"
FIG. 218. — Pholis, the rock eel. Right side. Nat. size. Photo, hy W. H. C. P.
spines are slender. The fish swim near shore, in dense schools. One species on the Californian coast is known as a "smelt," and is a good food fish.
FIG. 219. — Gasterosteus punyitius, the nine-spined stickleback; male (above) and female near the nest in rushes. The female is about to deposit its eggs in the nest.
238
ZOOLOGY
The sticklebacks are small, elongated fishes, having an extremely slender tail and a large mouth. The dorsal fin is preceded by two or more large isolated spines. The fishes live in either fresh or brackish water. In some of
FIG. 220. — Gasterostea.s bispinvaux, the two-spined stickleback. Above, nest with eggs, and male entering. Below, male depositing its mil on the eggs.
Figs. 219 and 220 are reproductions of water-color paintings in the Museum of Comparative Zoology at Harvard College.
the species the male builds an elaborate nest from bits of aquatic plants, firmly united by a special mucilaginous secretion. The nest, which is built among the plants of the stream, consists of a short cylinder, through the hori-
THE SMELT AND ITS ALLIES
239
zontal cavity of which the fish can lie while it deposits its eggs. The male is polygamous, and guards the single nest, which receives the eggs from various females (Figs. 219, 220).
The codfishes, among the most important of food fishes, are characterized by having ventral fins without spines, and articulated fin-rays, well-developed caudal fin, isocercal tail, and barbel on chin. Our common codfish (Fig. 221)
. 221. — Gad its morrhua, the codfish. About one-seventh nat. size.
After Storer.
occurs over the whole of the North Atlantic ; but the most important fishing localities are the banks near New- foundland, especially Grand Bank.
The flatfishes are peculiar among fishes in that they have the habit in the adult stage of lying on one side. In consequence the under eye migrates to the upper side, so that both eyes come to lie on the same side of the body. The mouth also tends to become unsymmetrical. The flatfish, consequently, illustrates well the principles of self- adaptation to a peculiar environment.
The catfishes are distinguished by the possession of four to eight long barbels around the mouth, and by the
240
ZOOLOGY
absence of scales on the body. They are characteristic of South America, but there are a large number of species in the United States, mostly found in the Mississippi valley
• ->>.•. X '
* .§ . * '
;« -*
V
X x\ X X VV
, v\V
NV
FIG. 222. — One of the flatfishes, seen from the upper side. Two-thirds nat.
sixe. Photo, by W. H. C. P.
and the Great Lakes, inhabiting deep or sluggish waters, and living in the mud. The common New England
FIG. 22-"». — Anicairus iirhtilosiix, the catfish. About one-half nat. size. Photo, of living animal by Dr. R. AV. Shufehlt, " Bull. U. S. Fish Com.," 1899.
THE KNELT ANT) ITS ALLIES
241
pecies is Ameiurus1 catus? the bull-head or horn-pout.3 t was with reference to this species that Thoreau wrote hat they are "a bloodthirsty and bullying race of rangers, ahabiting the river-bottoms, with ever a lance at rest and eady to do battle with their nearest neighbor." The tiff, jagged rays of the pectoral fins can make severe vounds. The great catfish of the Mississippi River, vhich may weigh up to 90 kilogrammes, is known as imeiurus lacustris.^ This, as well as most other species •f catfish, is much prized as food.
FIG. 224. —The brook sucker. After Goode.
The suckers are characteristic North American fish, ibundant in every creek, and consequently known to every over of woods and brooks. Characteristic is the form of ips, which are thick and drawn down at the corners.5 They ire rather sluggish fishes, and feed on small aquatic insects tnd suck up mud. They are not generally esteemed as ood, inasmuch as their flesh is coarse and very full of )ones. In the Mississippi valley, however, they are so ibundant and large that they are of some commercial mportance.
not curtailed. 2 Cat. 3 Fig. 223.
Living in lakes.
5 Fig. 224.
R
242 ZOOLOGY
The term "minnow" is applied to two distinct families of small fish. One of these is also known as " killifish." The killifish have a broad head covered with scales, and have well-developed teeth in the month. They occur in schools in shallow water on the shore, and ascend streams to their sonrce. They are carnivorous, and feed at the surface. In one species from the Southern coast, Heterandria l for- mosa,2 the male is only about two centimetres long, and is the smallest known vertebrate. Our commonest species on
FIG. 225. — Fumhdus heteroclitus, a killifish or shore minnow. Xat. size.
Photo, by W. H. C. P.
the shore, or in brackish water, is Fiindiilm 3 heteroclitus 4 (Fig. 225). The minnows of the other family have a nar- row head without scales, and with no teeth in the mouth. They occur exclusively in fresh water, and are known as "shiners." The " goldfish" is related to this group.
The pike and pickerel (Esox5) are roughly cylindrical fishes, with large mouth, elongated, depressed jaws, and strong, hooked teeth.6 They are large, voracious, fresh- water fishes, confined, with the exception of a single species, to the United States. The " muskallunge " of the Great
s, different ; <ii>r)p, avdpos, man, male. 2 Comely.
3 fundus, bottom. 4 erepo/cXtros, irregular or unusual.
5 f<ro£, a fish living in the Rhine, mentioned by Pliny.
6 Fig. 220.
THE SMELT ANT) ITS ALLIES
243
Lakes reaches a length of two metres. It is, fortunately, somewhat rare, otherwise there would be few other in-
habitants of our large streams.
FIG. 226. — Lucius luchts, the pike. About one-fifth nat. size. Photo, of living animal by Dr. K. W. Shufeldt, " Bull. U. S. Fish Com.," 1899.
The shad is a representative of a family — the herring family — which has played an important part in the civiliza- tion of Europe. There is an old adage in Holland to the
FIG. 227. — Alosa sapidissima, the shad. After Goode.
effect that Amsterdam is built on herring-bones ; and the Emperor Charles V. said that the herring brought greater wealth to the Netherlands than did America to Spain. Our common shad, Alosa1 sapidissima,2 ranges from New-
1 From Saxon all is, old name of the European shad.
2 Most delicious.
244 ZOOLOGY
foundland to Florida.1 Next to the Pacific salmon and cod, it is commercially our most important fish, for the catch of Atlantic shad for 1896 exceeded one and a half million dollars. The Pacific coast has been successfully stocked with shad from the Atlantic. The Atlantic shad, like the salmon, migrate up streams to deposit their eggs. The alewives have the same habit. The herring, on the contrary, spawn in the sea. As the common name, allied to the German Heer, an army, implies, they travel in great schools. The menhaden, which also occur in great schools, have of late years been destroyed in vast numbers to make fertilizers.
The eels are easily distinguished by their serpentine form, the absence of ventral fins, the long dorsal fin, and the rudimentary or absent scales. These fish occur all along our coast and ascend streams. During the day they lie hidden in mud and at night they feed, their principal prey being small aquatic animals, the young of other fish, and shrimps and crayfishes during the moulting period. On account of the narrowness of the gill-opening, they may live for some time out of water in a moist place. The reproduction of the eel was long a mystery. All sorts of creatures have in past times been supposed to produce them, ranging from the gods to water-beetles. They have even been thought to be generated from slime. We now know, however, that there are both male and female indi- viduals ; that the males live chiefly, but not exclusively, in the sea ; that reproduction occurs chiefly in the sea ; and that the young females come from the sea and pass up the rivers during the spring.
The pipe-fishes and their allies (Lophobranchii) include
Fig. 227.
THE KNELT AND ITS ALLIES
245
a number of aberrant forms. Some of these are greatly elongated, like the pipe-fish proper (Fig. 228) ; others are shorter and stouter, like the u sea-horse." All have an
FIG. 228. — Siphostomafuscum, the pipe-fish. Nat. size. Photo, by W. H. C. P.
elongated snout, and usually a long, slender tail. The body is encased in bony plates, and the male is often pro- vided with a brood-pouch, in which the developing young are carried.
Besides the bony fishes, which we have just considered in detail, there are various other classes of fish.
FIG. 22l>. — Petromyzon, the lamprey. One-fourth nat. size. After Goode.
The Cyclostomi, or lamprey eels, are the only parasitic vertebrates. In the adult stage they either live attached
246
ZOOLOGY
to the outside of other fishes, sucking their blood, or else
they may penetrate into the body cavity. They do not bite, because they have no lower jaw, and are known as "round- mouthed' eels.1 Lam- preys are found in the seas and in the rivers of the temperate zones. They occur on our Eastern coast and ascend rivers ; others live in the lakes of New York, in the Great Lakes, and in the Missis- sippi valley. In Europe they are much esteemed as food.
The Selachians include the sharks and rays, all inhabitants of the sea. They may be distin- guished from the bony fishes by the rough skin, beset with spines, and by the cartilaginous skele- ton. We have a num- ber of sharks on our Northeastern coast, of which the dogfishes and the sand-shark are the
i Fig. 229.
THE SMELT ANU ITS ALLIED
247
commonest (Fig. 230). They are all carnivorous animals and powerful swimmers. They feed on the larger Crus- tacea and fish.
The living Ganoidei are a remnant of a very extensive group which existed in geological times. North America is especially rich in existing representatives of this group, as of several other old groups, such as the turtles, tailed amphibians, and the king-crab. Of the five families of ganoids, four are represented in this country. In the following four paragraphs we shall consider a type of each of the native families.
The sturgeons have five rows of bony scales on the trunk and four barbels on the head.1 They occur both
FIG. 231. — Acipenser, the sturgeon. One-sixteenth nat. size. After Goode.
in the sea and in the Great Lakes and the rivers of the Central States. Although of large size, they feed for the most part on small aquatic animals, such as worms, insect larvse, and small fish. The flesh of some species is much used as food ; the eggs taken from the ovaries (roe) con- stitute a delicacy known as "caviare."
The spoonbill, which has an elongated, flattened snout and is almost without scales, is a large fish found in the Mississippi River. It is also called u paddle-fish " or " duck-bill catfish." It becomes two metres long and seeks small animals in the mud, which it stirs up with its snout.
i Fig. 231.
248
ZOOLOGY
The garpikes are known by their long snout (Fig 232). They are completely clad in an enamel coat of mail. They are of sluggish habits, but voracious, and their flesh is
FIG. 232. — Lepidosteus, the garpike. One-eighth nat. size. After Teimey.
valueless as food. One species is found in China, the others in the rivers of North America.
The bowfin (Amia1) occurs in the rivers and lakes of the United States. It has a short body, a blunt head, and
FIG. 233. — Amia calva, the howtiii. One-sixth nat. size. From Leuuis.
a long, dorsal fin (Fig. 233). It is the sole survivor of a formerly large family.
The Dipnoi 2 include only three rare foreign forms, which seem to form a transition between fishes and the higher groups, for some of them have lungs in addition to gills. From some such lunged fishes must the amphibia have arisen (Fig. 234).
Ancestry of Vertebrates. - The fishes, amphibia, reptiles, birds, and mammals, which are considered in this and the following chapters, constitute together the group of verte- brata, or backboned animals. All the animals treated of
1 dut'a, ancient name of a fish.
2 si
Si's, twice ; irvo-fj, breath.
TUE SMELT AND ITS ALLIES
249
Nit II
r- ...
- 3
c
—
fe
250
ZOOLOGY
at
FIG. 236. -- Ciona, a simple tunicate, o, mouth ; at, open- ing of atrium, or exhalant opening; st, stolon. After Leuckart aud Nitclie's dia- grams.
FIG. 238. - - Balanoglossus, the acorn- tongued worm. The proboscis at the anterior end is at the top of the figure (partly outside) ; behind it is an orange-colored collar: then follows the long, brown-red trunk. Nat. size. Photo, of living animal by W. H. C. P.
FIG. 237. — Botryllus, a compound tunicate. Nat. size. Photo, by W. H. C. P.
THE SMELT AND ITS ALLIES 251
in earlier chapters are invertebrates. Between verte- brates and invertebrates and connecting the fishes with more worm-like ancestors, is the lancelet or Amphioxus.1 This slender, rod-like animal is only 50 to 70 milli- metres long. Its internal structure shows its relationship with vertebrates ; it has the forerunner of a vertebral column and a spiral nerve and it has also gill slits like a fish, but it has no skeleton.2 It lives in sandy seashores in temperate and tropical zones. On our Eastern coast it is found from Chesapeake Bay south. It stands embedded in the sand, the tentacle-fringed mouth projecting above the surface. It feeds on minute organisms of all sorts.
Of the invertebrate groups, that of Tunicata lies nearest to the stem from which the vertebrates arose. The adult animals, however, are very different from vertebrates, for they are attached (Fig. 236), and sometimes even form colonies (Fig. 237). But the young animals are much like tadpoles of frogs ; not merely superficially, but in their structure. Going further back it seems clear that vertebrates have developed out of the worms. A very worm-like animal, which seems to foreshadow the verte- brates in having gill slits and the forerunner of a back- bone, is common in our sandy beaches. This is Balano- glossus3 — the acorn-tongued worm, so called from the shape of its proboscis (Fig. 238).
i', both [endsj ; 6£tfs, sharp pointed. 2 Fig. 235. 3 /SdAaws, acorn ; 7\£(rcra, tongue.
252
ZOOLOGY
APPENDIX TO CHAPTER XVI
KEY TO THE PRINCIPAL ORDERS OF FISHES
«i. Without skull, paired fins, or heart ; blood color-
ACoo •••*•• •••
a*. With skull, heart, and red blood [Craniota]. 61. Without lower jaw or paired fins
b-2- With lower jaw and paired fins [Gnatho-
stomij. Ci. Intestine with spiral valve.
d\. Without an operculum covering the gill openings ; scales toothed
dz- Operculate ; skin with enamelled
scales.
e\. Breathing by means of gills only . . .
e2. Breathing by both gills and a lung ....
c2. Intestine without spiral valve ; skele- ton bony
Acrania
(Ex. Amphioxus)
Cyclostomi
(Lamprey eels)
Selachii
(Sharks and rays)
Ganoidei (Ganoid fishes)
Dipnoi
(Mud fishes)
Teleostei
(Bony Fishes)
KEY TO THE SIX SUBORDERS OF TELEOSTEI «i. Gills comb-like.
J»i. Intermaxillaries and maxillaries movable
on each other. Ci. Dorsal fin, anal fin, and ventral fin
spinons anteriorly. d\. Pharyngeal bones distinct . . Acanthopteri
(Perches, darters, sunfishes, toadfishes, sculpins, silversides,
sticklebacks)
d-2. Pharyngeal bones united . . Pharyngognathi c2. Dorsal, anal, and ventral fins without spines.
APPENDIX TO CHAPTER XVI
253
fl-2-
d\. Ventral fin, when present, placed on throat or breast ; air-bladder without air tube . . . Anacanthini
(Codfishes, flatfishes)
do. Ventral fin, when present, placed ventrally ; air-bladder with air- tube Physostomi
(Smelt, trouts, whitefishes, catfishes, suckers, minnows,
shads, eels)
&2. Intermaxillaries and maxillaries united with
each other and with skull . . . Plectognathi Gills small, tuft-like ; body covered with bony plates Lophobranchii
(Pipe-fishes)
CHAPTER XVII
THE NEWT AND ITS ALLIES
THE newts belong to the class Amphibia,1 or, as it is also called, Batrachia, characterized by the fact that, while they have no rayed fins like fishes, but legs instead, they have functional gills during at least a part of their free life. The eggs, which are laid in water, are without a hard shell.
The little newt Diemyctylus viridescens 2 is found in New England and westward to the Mississippi valley. During different stages of development it assumes widely different habits. The eggs are laid during the spring in water, where they hatch after three to five weeks and appear as olive-colored tadpoles with external gills. At this time they have an exclusively animal diet, feeding on minute Crustacea, larval insects, snails, and aquatic worms. In August the gills and tail-fin become absorbed, and the transformed animal takes to land and lives under stones at some distance, it may be, from water. At this time it has a vermilion color,3 and feeds on spiders, insects, and earthworms. After two or three years the newt assumes a
1 Keys to the Orders of Amphibia and to the families of Urodela will be found in the Appendix to this Chapter, page 266.
2 The newt of the Pacific coast is D. torosus.
3 The color and habitat of the terrestrial young Diemyctylus are so different from the fully matured aquatic form that the two were formerly regarded as distinct species.
254
THE NEWT AND TTS ALLIES 255
brown color, and eventually the olive-green or viridescent color of the adult. It then takes to the water and is found especially in springs, and in ponds and brooks fed by springs. It now subsists on various aquatic worms, crustaceans, insects, and mollusks. The newt gains oxygen for respiration by swallowing air mixed with water.1
Distribution.- -The Amphibia live chiefly in tropical and subtropical countries, although a number of them belong to the colder parts of the temperate zone. There are no strictly polar species, although one species of frog extends from Massachusetts north to Alaska. The Gymnophiona 2 are confined to tropical countries and are most abundant in South America. They live, like earthworms, in the ground and have more or less rudimentary eyes. The Urodela are confined in their distribution to the Northern Hemisphere (excepting that two or three species extend along the Andes south of the equator). North America is especially rich, both in species and individuals, of Uro- dela. The Anura, or toads and frogs, are found in all parts of the world, especially in South America and Australia.
Families of Urodela. — Of the American Urodela,3 the Sirenidae include the Siren,4 or mud-eel, of the Southern States. This species becomes 60 centimetres long, and is of a dark lead color (Fig. 239). It is needlessly feared by the negro rice cultivators, who slaughter it in great numbers.
1 Newts may be captured by sweeping with a net the muddy bottoms of small, spring-fed pools. They can be kept for months in an aquarium, where they should be fed thrice a week with earthworms or freshly chopped beef.
2 From yv/j.v6s, naked ; 60iW, a fabulous, snake-like animal.
3 ovpd, tail ; 577X05, conspicuous. * A mythological creature.
256
ZOOLOGY
S-i
CD
p
6
+3
•— J rr- +->
a .22
01 2 0 c3
J^ 3
C--J
6
THE NEWT ANT) ITS ALLIES 2">7
The Proteidae 1 include our Necturus, commonly known as mud-puppy or water-dog, which is found from the Hudson River to the Mississippi valley, and is very abundant in the Great Lakes. Its external gills are very large, and red with the blood flowing in them. It feeds on small water-animals. In April or May it lays eggs about the size of a pea. A curiously modified form of Necturus occurs in caves (Fig. 240). Another member of this family is the cave u olm "' of western Austria.
The Amphiumidae 2 include only the Congo snake of the Carolinas and Gulf States. This black, snake-like Urodelian is about a metre long, and lives in bayous and muddy dit dies (Fig. 241). It has the entirely undeserved reputation of being injurious.
The Cryptobranchidae 3 include the so-called "hell- bender' of the Ohio valley and south.4 It is a very voracious scavenger of the water, and bites the hook fiercely. It is noted for its great tenacity of life under unfavorable conditions. The only other living repre- sentative of this family is the Japanese giant salamander, which becomes three metres long.
The Amblystomidae 5 include some twenty-five species belonging to five genera, four of which occur in northern
O O o
and eastern Asia, and the fifth, Amblystoma, is confined to the United States and Mexico, excepting one species, occurring in Siam. The common species of New England and the Central States is known as the Spotted Sala-
1 Hporeys, a sea-god possessed of the power of changing himself into different shapes.
'2 Probably a modification of a native name.
3 /cpi'Trros, hidden ; /3/>d7xio;>, S1^-
4 Fig. 242. 5 From d/i/SMs, blunt ; crT6/j.a, mouth.
8
258
ZOOLOGY
mander. It is about 15 centimetres long, and black, with a series of yellow spots on each side of the back. It lays
•'" •"•1111,-v^
^— *MniK»
^*_;v
FIG. 242. — Cryptobranchus, the " hellbender." Reduced. From " .Stand- ard Natural History."
eggs in springs or ponds during April ; the dark gray eggs are contained in great masses of jelly which are
FIG. 24o. --The larva of Ambli/stowa tif/riiium, the Axolotl stage of the tiger
salamander. From Mivart.
THE NEWT AND ITS ALLIES
259
attached to sticks at or near the surface of the water. The larvae of the more southern species often reach a size considerably larger than the adult, and breed before the gills are absorbed. In a Mexican species the larval state is never transcended. The larva of Amblystoma (Fig. 243) was formerly described, indeed, as a distinct species.
The Plethodontidae a and Desmognathidae 2 include a num- ber of small Urodeles, having a close general resemblance
Fi<;. 244. — Plethodon, the red-backed salamander. Slightly reduced. Photo.
of living animal resting on a leaf.
and similar habits. Plethodon, of the eastern United States, is lead-colored above, very often with a broad, red dorsal band (Fig. 244). It is found under logs, and is very active. Spelerpes3 is lemon-yellow and white below, and Desmognathus is brown above, with gray or
s, abundance ; odo^s, 656fTos, tooth. 2 5e<r/x6s, bond ;
jaw. 3 (TTTTjAcuoj/, cavern ; epir-rjs, a crawler.
260 ZOOLOGY
purplish spots on the sides. Both Spelerpes and Desmo- gnathus live in and about running brooks, under stones and fallen logs. Their eggs are attached to the under surface of submerged stones. The adults are easy to keep in confinement in a moist fernery. They may be obtained out of doors all the year round, excepting during the time of deep snow. There are four species of Spelerpes and three species of Desmognathus in the northern United States.
Metamorphosis. — As we have seen, all Amphibia have gills while young, but some lose them before maturity while others retain them permanently. Those species which retain the gills pass their whole life in water ; the others may live on the land. The loss of gills is asso- ciated with the assumption of a land life. In the Ambly- stoma we have species which are curiously intermediate between the two classes in that they may retain their gills, tail-fins, and other structures adapted to aquatic life,1 even to the time of reproduction ; or they ma}T lose their gills and tail-fins. The first result follows if they are pre- vented from coming on land ; the second, if they are forced to leave the water. The capacity of the Mexican Axolotl for either becomino- an adult or remaining1 a larva was
o o
first shown by some experiments of the German naturalist Weismann and a pupil of his. It Avill be seen that when forced to live in the water Axolotl retains permanently a larval condition ; and one would never know that in this larval condition the animal is not adult were it not for the accident of its sometimes becoming adult. It is quite possible that all of the Urodela which retain their gills throughout life may formerly have had a gill-less adult stage which is now lost.
1 Compare Fig. 243.
THE NEWT A XI) ITS ALLIES
Early Development of Urodela. — The eggs of Urodela are deposited in a gelatinous mass in water, and are attached to submerged plants, or to other objects in the
FIG. 5.
FIG. 7.
I IG. 10.
FIG. 12.
FIG. 6.
FIG. 8.
FIG. ii.
FIG. 13.
FIG. 14.
FIG. 9.
f
FIG. 17.
FIG. 15.
FIG. 1 8.
FIG. 16.
FIG. 19.
FIG. 245. — Developmental stages of Spelerpcsbilineatus. Fif/x. '>-!>, neural groove beginning to form; Figs. 10, 11, iieural groove closed; Flys. 7?, 7.7, liead beginning to form; Fiyx. 14-ln, tail formed, yolk absorbing; Fiy. 17, embryo capable of moving in egg membrane : Fiy. 18, embryo just able to swim ; Fiy. lit, three days after hatching. The letters indicate the successive stages. After H. H. Wilder, from ''The American Naturalist."
water, either singly or in masses, according to the species. The eggs contain much yolk ; consequently the cleavage is partial, and the embryo seems to develop on a small part
262
ZOOLOGY
only of the yolk and for some time after hatching the yolk mass hangs as a lump on the under side of the embryo. Very early a deep groove, bounded by a pair of folds, arises on the edge. This groove is large in front (Fig. 245, />). It forms the beginning of the brain and spinal cord. The feathery gills and the beginnings of the appendages
SS^L
Fi<i. 246. — Pipa americana. Female with young in pits on its back.
next sprout out, while the trunk continues to elongate and assume the form of a young salamander (Fig. 245).
Families of Anura. - - Of the Anura there are eight or ten times as many species as there are of the Urodela. They are distributed into nearly a score of families. Of
THE XEWT AND ITS ALLIES
263
these a few of the more interesting deserve to be men- tioned.
FIG. 247. — Section through skin of back of Pipa amarircuia, showing develop- ing embryos. Much enlarged.
The Pipidae include the South American Pipa, note- worthy because of the habit which the female has of brooding its young in pits of the skin on her back (Figs. 24ti, 247).
FIG. 248. — Nodelphys, brooding tree-frog, female, from Venezuela. In the hinder part of the trunk the opening to the brood-pouch is seen. From a water- color painting at the Museum of Comparative Zoology at Harvard College.
The Hylidae, or tree-toads, include various arboreal species in which the ends of the fingers are modified for
264
ZOOLOGY
holding on to objects by suction. Of these there are over one hundred and seventy species, especially abundant in tropical America. In one member of this family the female has a pouch on the back, opening in the hinder third of the trunk (Fig. 248). In this the young arc
FKJ. 2-49. — J>t(fo lentlginosus, the American toad. Photo, of living animal,
resting on the ground, by W. H. C. P.
brooded. The most common tree-toad of the northern United States extends from Canada to Florida, and west to Kansas. It is variable in color, being green or brown, according to the color of the background, leaf, or bark, on which it is resting. It has a loud, coarse trill, often
THE NEWT AND ITS ALLIED
erroneously regarded as a weather sign. The eggs are
\j t~} CJ CJ <J
laid in small bunches in shallow water.
The Bufonidae include the common toads which occur all over the world. Our Eastern toad1 inhabits nearly all the United States east of the Rocky Mountains.2 It is crepuscular in its habits, and feeds chiefly on insects and worms. The eggs are deposited in two long, parallel strings of albumen, which lie coiled at the bottoms of
FIG. 250. — Runa clanutano, green frog. Nat. size. Photo, of living animal
by W. H. C. P.
ponds, hatch out in May, and metamorphose about a month later.
The Ranidae are almost confined to the Northern Hemi- sphere and the East Indies. In the northern United States there are some eight species, of which the commonest are: the leopard-frog, of green color, with irregular black blotches edged with whitish ; the pickerel-frog, light brown, with two rows of oblong square brown blotches
JBufo Icntiyinosus.
- Fig. 249.
266 ZOOLOGY
on the back ; the wood-frog, living in damp woods, pale reddish brown, with a brown band on the side of the head ; the green frog, of uniform bright green to brown color, with numerous small dark spots, and with glandular folds (Fig. 250) ; and the bull-frog, of great size, green, with small faint spots on the back.
APPENDIX TO CHAPTER XVII
KEY TO THE ORDERS OF AMPHIBIA
«i. Appendages and tail lacking; body worm-like ;
skin furrowed transversely .... GymnopMona
a2. Appendages present.
61. Body elongated ; tail present ; generally 4, but rarely only the 2 anterior appendages present . ..... Urodela
&2- Body short ; in adult condition tailless . Anura
KEY TO THE FAMILIES OF URODELA
a\. External gills persistent throughout life ; maxil- lary bone small or wanting. 61. Body eel-like ; hind legs absent ; jaws with
horny sheath ...... Siroii'lir
1>>2. Body salamander-like ; hind limbs present ;
teeth on jaws Proteidcu
«2- External gills normally disappearing in adult ;
limbs 4 ; maxillaries present. &i. Side of neck with spiracular opening ; no
eyelids.
ex. Limbs rudimentary .... Amphiwnidai c-2. Limbs well developed .... Cryptobranchidce b->. Side of neck without spiracular opening in adult ; eyelids present.
APPENDIX TO CHAPTER XVII
267
Ci. Palatine teeth in transverse (or nearly
transverse) series. d\. Vertebrse doubly concave.
e\. Parasphenoid without teeth ;
tongue large ; toes 4-5 e-2. Parasphenoid with teeth ;
tongue small d*. Vertebras convex behind only ;
tongue moderate ; toes 5 C2. Palatine teeth in 2 longitudinal series, diverging behind ....
AmblystomidcB
Plethodontidce
Desmognathidce
Pleurodelidcp. (Ex. Diemyctylus)
CHAPTER XVIII
THE LIZARD AND ITS ALLIES
THE lizards belong to the class of Reptiles,1 which are vertebrates in whose skin horny or bony scales or plates are formed. They constantly breathe by means of lungs, and lay large eggs provided with a tough leathery or calcareous shell.
The Sauria, or lizards, constitute a large order charac- teristic of the tropical and subtropical countries and reaching the maximum of its development in South America, while in the northern continents it is relatively poorly represented. Lizards are, as a rule, carnivorous, and since they destroy insects injurious to vegetation, they may be counted as beneficial to man.
Anolis2 is one of the family Iguanidae,3 a large group of lizards characteristic of the Western Hemisphere. The family is known by the thick tongue, by a large scale in the middle of the head in front of the eyes, and by the fact that all four legs are Avell developed. The genus Anolis contains eighty tropical species. Our species lives in pine woods from the latitude of Tennessee south to the Gulf and the island of Cuba. Its graceful form and bright colors make it one of the most beautiful of lizards. It
1 A key to the four orders of Reptiles will be found in the Appendix to this Chapter, page 280.
- Atwli, native name. 3 Native name,
268
THE LIZA It I) AND ITS ALLIES 269
lives on trees, eats insects, is not timid, can live well in confinement, and, like the chameleon of Europe, has the power of changing its colors from bright green to dirty brown. Besides Anolis we have various other lizards of the family Iguanidre. The horned toad of the Southwest, which has a broad, flattened body and long spines on the head, and lives in dry, sandy places, is a familiar object.1 In the South Central and Southern States lives the elon- gate " swift " of varying color, often with black, irregular
FIG. 251. — Phrynosoma, the horned toad. Photo, by E. R. D.
cross bands above, with iridescent colors on the throat of the male, and with large, strongly keeled scales and a slender tail. The largest of the Iguanidse is the " leguan * of the West Indies and South America, which gains a length of 1.75 metres, or over five feet.
The family Varanidae,2 or water-lizards, contains the largest known lizards. The Nile varanus attains a length of nearly tAvo metres. It lives on the rivers of Africa, feeds on small Crustacea, birds, birds' eggs, frogs, fish, and occasionally also on young crocodiles and crocodile eggs.
1 Fig. 251. 2 Latinized from the Arabic word waran, lizard.
270
ZOOLOGY
The ancient Egyptians regarded these crocodile-like lizards as the greatest enemies of the crocodile.
The Lacertidae,1 which are common in middle and south- ern Europe, are agile, harmless creatures, often of bright colors, and are commonly and favorably known. The more
FKJ. 252. — Lacerta viritUx, the green lizard of Europe. After Brehin.
abundant are the " green lizard" (Fig. 252), the ''sand- lizard,"' and the "wall-lizard" of the Latin countries.
The Helodermidae include the largest lizard of the United States, the so-called kt> Gila monster," which in- habits New Mexico, Arizona, and the country southward. The lizard is colored brown, with reddish spots and numer-
1 From lacerta, lizard.
THE LIZARD AND ITS ALLIES
271
ous yellowish punctatipns (Fig. 253). It is nocturnal in its habits and its bite is very poisonous, although not often fatal to man.
The family Anguidae, or slow-worms, includes the famous glass-snake or joint-snake of the South. This snake-like lizard has no legs, or only rudiments of the hinder pair. It is noted for the ease with which it breaks in two when
FIG. 253. — Heloderma, the Gila monster. About two-fifths nat. size.
From Brehm.
struck or lifted by the tail. This result is due to the fact that, as in certain other lizards, the vertelme of the tail are unossified along the middle plane, so that they separate at this point upon the slightest blow. The muscles of this species seem also to be arranged so as to facilitate sepa- ration. In Europe there is a lizard of this family, the so-called u blind- worm " (having, however, well-developed
272 ZOOLOGY
eyes), which is found in retired localities, from which it comes out, especially in the evening, to capture earth- worms and slugs.
The Chameleon famed in literature comes from Africa. Its change of color depends upon the possession of several layers of different color in the skin, which layers can be separately expanded or contracted as required, as a result of which some one color comes to predominate. It cap- tures insects, a habit which is facilitated by its power of
FIG. 2r4. — Chameleo, the chameleon. From Leunis.
protruding the tongue to over half the length of its body and bringing the sticky end in contact with its prey. The protrusions and retractions of the tongue are effected witli marvellous rapidity (Fig. 254).
While in point of size the lizards of geologically recent times are inconsiderable, those of former epochs were huge. These former or fossil lizards were most charac- teristic of the middle life era or the Mesozoic age. They belong to three main groups; namely, swimming, walking or wading,1 and flying lizards. The swimming lizards were
1 Fig. 254.
THE LTZART) AND ITS ALLIES
070
_ i • >
sometimes over 10 metres long% and had feet modified
O
as paddles. The land lizards were elongated, three-toed, carnivorous reptiles, with hollow leg bones like birds. In the flying lizards, a strong compact body was provided with hollow, air-filled bones, and locomotion was effected by a huge membranous expanse stretched between the
FIG. 255. — Hadrosaurus. From reconstruction model. Osborn, " Kept.
Amer. Mus. Nat. Hist."
elongated posterior finger, the trunk, and the hind legs. The spread of the wing was about three feet.
The Chelonia,1 or turtles, form an order distinct from the lizards. They are characterized by a depressed form, a bony case, and toothless jaws. Like other reptiles, they are most abundant in tropical countries, since the high
turtle.
274 ZOOLOGY
external temperature compensates in a way for the insuf- ficiency of the mechanism for maintaining from the inside a high blood temperature. Turtles are abundant in Africa, and are much commoner in North America than in Europe. Three families of Chelonia may be distin- guished. A short account of each follows.
The family Chelonidae includes certain marine turtles. Turtles live in all oceans and may acquire a weight of as
Fi<;. 2")ii. — Hawkbill-turtle. Much reduced. From Brehra.
I
much as one thousand pounds. The green-turtle, used in making soup, occurs on the Atlantic coast as far north as Long Island. From the hawkbill-turtle (Fig. 256) comes the tortoise shell used in certain ornaments. In the leather-back the shields are incompletely ossified.
The family Trionychidae l includes our soft-shelled tur- tles, which live in rivers or ponds of the Mississippi valley and the Gulf drainage basin (Fig. 257).
1 rpt's, tliriec ; 6w£, claw.
THE LIZARD AND ITS ALLIES
275
The family Testudinidae l includes the hard-shelled, fresh-water and land tortoises. < )ur snapping-turtle is distributed from Canada to equa- torial South America. It feeds on fish and lays from forty to fifty eggs, which it buries at a depth of about a metre. The alligator snapper of the Gulf States attains the length of a metre, and is re- garded as the " most ferocious and, for its size, the strongest of all reptiles." The box-tortoises oc- cupy the northeastern and central parts of North America. They are well known by the fact that
the body is short and high, the FIG. ir>7. - Trionyx, three- plastron is provided with a mov- able hinge, and the carapace is colored black and yellow.2 Other
clawed turtle of the Mis- sissippi valley. Reduced. From Leuuis.
FIG. 258. — Tcrmpene Carolina, the box-tortoise.
by AY. H. C. P.
1 From tcst«, a shell.
Photo, of living' auimal
2 Fig. 258.
ZOOLOGY
common tortoises of the eastern United States are the musk- turtle, told by a strong odor of musk ; the painted turtle, of greenish black color and with marginal plates marked with bright red ; the speckled tortoise, black with round orange spots ; and the wood tortoise, with keeled shell, and plates marked with concentric stria3.
The order Ophidia : comprises the snakes, characterized by the elongated body without appendages, and by the
FIG. 259. — Eutfenia, garter-snake, dorsal view. Photo, by E. R. D.
absence of eyelids. Like other reptiles, the snakes are chiefly tropical, but inhabit also the temperate zones. They feed on living animals.
The family Colubridae 2 includes the great majority of our common non-venomous snakes, such as the garter- snake,3 water-snake, black-snake, milk-snake, and spread- ing adder. Allied are the boas of South America and the pythons of India, which attain the length of six metres or
c!0ts, serpent.
2 coluhra, serpent.
3 Fig. 259.
THE LIZARD AND 77\s ALLIED
more. Not being' poisonous their bite is not dangerous, l>ut they attack large birds and even medium-sized mam- mals and crush them to death in the folds of their body.
The family Elapidae : includes the large venomous ser- pents of the East, the cobra of the East Indies, and the asp of the Egyptians. The bite of these serpents is quickly
m \
i \ , i
IR^^fevfck
BMMb.
Fi<;. 2HO. — Elapx coralluia, a harlequin snake of South America allied to the l)ead-snake of the South. From " Standard Natural History," after Brehin.
fatal to man. To this family belongs also the bead-snake of our Southern States, which is however harmless (Fig. 260).
The Crotalidae 2 include the rattlesnakes, characteristic of America.3 Of this family the most dangerous is the water-
. an unknown snake of the ancients.
/, clapper. 3 Figs. 261, 262.
278
ZOOLOGY
FIG. 2(il. — Crotalus, the rattlesnake. Photographed as the snake was about to strike. Taken in Ari/ona and kindly lent by H. ~\V. Menke, Chicago, 111
FKI. 2(!2. — The rattlesnake. The recoil after striking. Photographed in Arizona and kindly lent by H. AV. Menke.
Note in both figures the elevated rattle, toward the right.
THE LIZARD AND ITS ALLIED 27!)
moccasin or black moccasin, which inhabits the Southern States, and give;; no warning noise as does the rattlesnake. The copperhead of the eastern half of the United States is also dangerous, but is mostly confined to wooded, moun- tainous regions. The rattlesnake was once common over the whole of the Northern States as far west as the Rocky Mountains, but it is now nearly exterminated in well- settled districts. Related to these are the venomous vipers of Europe.
The order Crocodilina contains only some twenty species, distributed in three genera. The gavial is the crocodile
FIG. 2b'o, — Head of Allii/ator ini.^f.^ippieiifiis, the Mississippi alligator.
From Leunis.
of the (ranges River. It captures even large mammals and man. The crocodile in the strict sense is found in the Nile and other African rivers, in certain countries on the western border of the Pacific, and in northern South America, Central America, and the Antilles. The American alligator, which has a different arrangement of the denti- tion from the crocodiles, occurs in seven slightly differing species, all of which are South American excepting the alli- gator of our Southern States. It feeds on fish, and attacks horses and even man (Fig. 2(53).
280
ZOOLOGY
APPENDIX TO CHAPTER XVIII
KEY TO THE FOUR ORDERS OF REPTILES
«i. Trunk enclosed in a case composed of a dorsal and a ventral shield (carapace and plastron) ; jaws without teeth .......
«.j. Without encasing shields ; teeth on jaws.
b\. Teeth in special cups or alveoli ; 4 legs ;
cloacal opening a longitudinal slit f>-2. Teeth not in special alveoli ; cloacal opening a
transverse slit, fi. Shoulder girdle and sternum present ;
eyelids usually present
c-j. Shoulder girdle and sternum absent ; eye- lids absent ; no feet ....
Chelonia
Crocodilina
Sauria
CHAPTER XIX
THE ENGLISH SPARROW AND ITS ALLIES
THE term "English' sparrow is somewhat of a mis- nomer, for at the time it was introduced into our country this bird ranged over all Europe, where it is known as the Jwuse sparrow. The history of the spread of this bird shows us in a vivid way what are the successful qualities among birds. Originally this sparrow was confined to middle Europe, and probably made its way into Germany at the time of the Romans. It has since swept all over Europe, including the British Isles, and has penetrated even into Siberia. It has crossed the Mediterranean and is found along the Senegal River, and, probably through human agency, has penetrated to the Cape. It lias been transplanted voluntarily by man to North America, Australia, and Java. It seems to occupy among birds the place taken among mammals by the rats. Crafty, pugna- cious, obtrusive, thieving, dirty, it has become a nuisance wherever it has penetrated. But just these pushing quali- ties, combined with small size, great hardiness, a universal diet, and immense fecundity, have enabled it to make its Avay against all competitors. Its introduction into America can only be regarded as a deplorable blunder.
Spread of English Sparrow in America.- -The first im- portations of the house-sparrow (Passer domest.icus) to North America were made at Brooklyn, New York, in 1850
281
282 ZOOLOGY
and 1852. The second importation survived and multiplied. Subsequent importations were made to Maine, Rhode Island, and Pennsylvania, so that by 1870 the sparrow was firmly established in the eastern United States. From this time on the sparrow spread at a rate unparalleled by any native bird. By 1886 it had spread as far west as Kansas, and had established colonies at Salt Lake City,
i^
San Francisco, and other outlying regions ; and through- out this territory it occurred in great abundance. Since then it has penetrated west to the Rocky Mountains, and south to Texas. This extraordinary spread has been due to several causes. As already suggested, the bird can adapt itself to various climatic conditions, and its fecundity is very great. Thus in our Southern cities there are from five to six broods a year, and from four to six young in each brood. Assuming that twenty-four young, half of them females, are produced by a pair each year, and that all the females breed when one year old, and successively for ten years, and that there are no deaths, then in the tenth year 138,000,000,000 individuals will have been pro- duced from the original pair. To the realization of the possible maximum of reproduction there are, however, many checks, especially the destruction of birds by ac- cidents, disease, and beasts and birds of prey.
Food of English Sparrow. - The house-sparrow was in- troduced for the purpose of destroying or holding in check the wt canker-worm" and the various other caterpillars which destroy our fruit, forest, and shade trees. There is much doubt, however, whether the house-sparrow is at all effi- cient in the way of destroying insect pests, while it is quite certain that it fights with and drives away our native insect-eating birds. More important still, it de-
THE ENGLISH SPARROW AM) ITS ALLIES 283
stroys large quantities of grain in the field, as well as many kinds of garden produce, so that, on the whole, the English sparrow must be reckoned destructive to agri- culture. Of late years it has come into our Southern markets as a substitute for the rice-bird.
Increase of Exotic Species. - The extraordinary spread of the English sparrow after importation to this country is not wholly explained by its large fecundity; for although equally reproductive in Europe, it ^increases less rapidly there than here. Also it is not due to any peculiarity of our country, for the bird is a similar pest in Australia. Similar facts concerning the spread of other animals lead us to conclude that it is the new country which permits the rapid spread and consequent destructiveness. Thus when the cabbage-butterfly (Pieris rapce) was brought to this country it spread with such rapidity that, starting in 1860 at Quebec, it has now spread all over the United States as far as the Rocky Mountains. Again, the grape- vine insect pest, Phylloxera, a native of this country, but not particularly destructive here, has been accidentally transported to France, and there it lias wrought great havoc in the vineyards. Another instance, this time of an aquatic animal, shows the same result : the periwinkle, Littorina littoria, now the commonest snail on the seashore north of New York, has migrated down the shore from Halifax since 1868. This old species in the new country lias almost driven out the other shore mollusks, to such an extraordinary degree has it multiplied. Now why should animals in a new country develop with such unusual rapid- ity ? It is because coming into a new country they have left behind them their natural enemies, and there has not yet been time for them to acquire new ones. Eventually
284
ZOOLOGY
the new enemies are gained or their old ones overtake them, and then the numbers of the exotic form become reduced ; a new equilibrium becomes established.
The English sparrow belongs to the family Fringillidae, which includes sparrows and finches. This is a large
t
Fid. l'<)4. — The American crossbill (Lo'j-'m
family, comprising over five hundred species, found in all parts of the world, excepting, originally, Australia. In the United States this is the largest family of birds, com- prising in most places about one-seventh of the species. Among common or striking native Fringillidse may be
THE ENGLISH SPARROW AND TTs ALLIES
mentioned the crossbills,1 yellow-bird, vesper-sparrow, white-throated sparrow, tree-sparrow, chipping-sparrow,2 snow-bird, song-sparrow, fox-sparrow, chewiiik, cardinal grosbeak, rose-breasted grosbeak, and indigo-bird. Most of these birds are known to every country boy.
The family of Turdidae, <>r thrushes, includes several common American birds, — the robin, abundant about
FIG. 2<!5. — Cliipping-sparrow (tii>iz<>ll<i Nn<-i<tft*).
houses during the summer but for the most part migrat- ing south from New England during the winter : the wood
o o o
or song thrush,8 one of our finest songsters; the bluebird, one of the earliest of our migrants, with u the sky on its back and the earth on its breast."
The family of Sylviidae comprises the " warblers " of the Old World. Here belongs the European nightingale. Its common representative in this country is the ruby-crowned kinglet (Fig. 267).
1 Fig. 204.
2 Fig. 205.
Fig. 2(50.
28(3
ZOOLOGY
The family of Paridae includes the titmice, or tits and nuthatches. The tits are chiefly Old World birds, but we have a common representative in the black-capped chicka- dee, well known from its cheerful whistle. In this family
Fn;. 2(i(i. — Wood-thrush (Turiltts
belong the nuthatches which run over tree-trunks, head up or down, indiscriminately (Fig. 268).
The family of Certhiidae includes the little brown creeper which runs over tree-trunks much as the nuthatches do and uses its tail-feathers as props against the tree-trunk (Fig. 2l JO).
THE ENGLISH SPARROW AND TTS ALLIES 287
The Troglodytidae, or wrens, are characteristic of South America, but some have spread into North America and north- ern Europe. Our house- wren, which is a near relative of the European house-wren, is an ac- tive little brown bird, with a sharply bent-up tail.1 In this same family belong the mock- ing-birds, the centre of whose distribution is Central America, the \Vest Indies, and the south-
FIG. i>r>7. — Golden-crowned king-
let (R
ern United States. The large brown thrasher and the cat-bird are familiar over the country. The mocking-bird does not
O
o^et far north into New
o
England. It is regarded by many as superior to the nihtinale as a
snger.
FKJ. 2(iS. — White-breasted nuthatch (S:tta carolinensis) .
The family of Mnioti- lidae, or " wood - war- blers," is the peculiar glory of America. It
1 Fig. 270.
ZOOLOGY
contains numerous small, mostly brilliantly colored birds, which migrate. Although a few of .them- -like the red- start, the Maryland yellow-throat (Fig. 271), the redpoll warbler, the chestnut-sided warbler, and the yellow war- bler- - are abundant, few of the thirty -five or forty Eastern
. l'(>it. - - Brown creeper ( Ccrithia familiar if) .
FIG. 270. -- House-wren (Troylodyt.es aedon).
species can be said to be commonly known except to careful observers of birds ; for during the migrations they hide in thickets, and are extremely shy.
The Vireonidae include the vireos, or greenlets, bright, handsome, and exclusively American birds. The com-
THE ENGLISH SPARROW AND ITS ALLIES 289
monest species are the red-eyed vireo (Fig. 272) and the yellow-throated vireo.
The Laniidae, or shrikes, are of world-wide distribution. They are vigorous, pugnacious birds, which have the habit
Fi(i. 271. — Maryland yellow-throat (_G?ot-hlypis trichas).
of impaling grasshoppers and other small animals upon thorns, and leaving them there. In Germany there is a tradition that the shrike daily impales nine victims, and it is hence commonly called Neuntodter, or u ninekiller." The
u
290
ZOOLOGY
FIG. 272. — Red-eyed vireo (Vireo
FIG. 273. — Great northern shrike (Lanlus
THE ENGLISH SPARROW AND ITS ALLIES 291
impaling seems to be done chiefly in the winter time, and apparently has for its purpose the storing of food against possible famine. Among birds frequently destroyed by them is the English sparrow, and it has been suggested that the shrikes should be encouraged to live in parks of cities
FIG. 274. — Cedar waxwing (Ampelis cedro
infested by sparrow pests ; but unfortunately the shrikes do not confine themselves to this intruder. We have two species of shrikes, a northern (Fig,, 273) and a southern. The Ampelidae, or waxwings, are found over the Northern Hemisphere. They are migratory, go in flocks, feed on
9Q9
«il«7 —I
ZOOLOGY
insects and fruits, and chatter rather than sing. Our commonest species is called "cedar-bird " (Fig. 274).
Fio. 275. — Barn-swallow
The Hirudinidae, or swallows, are found over the world. They are powerful fliers, and are insectivorous. Formerly all of them bred in boughs, cliffs, and hollow trees, and
some species still retain these habits. The best-known species are the bank-swallows, which, living in colonies, form numer- ous holes in railroad cuts and sandbanks in general ; the white-bellied swallow, abundant about water ; and the barn-swal- low (Fig. 275), with a chestnut
Fi<;. 276. —Nests of barn-swal- & .
low. Photo, by D. and s. belly, which builds its nest in the
rafters of our barns (Fig. 276).
The Tanagridae, or tanagers, are exclusively American, and belong especially to the tropics. They live in the
THE ENGLISH 8PAKKO1V AND ITS ALLIES 293
woods, and feed on berries and fruits. The northernmost member of the family is the scarlet tanager of the eastern United States (Fig. 277).
The Icteridae include numerous species with different habits. These are also confined to America, and are especially abundant in the tropics. They feed, for the
FIG. 277. — Scarlet tanager (Piranya erythomelas) .
most part, on seeds. The commonest representatives are the crow blackbird,1 of large size and iridescent plumage ; the Baltimore oriole, which weaves a hanging nest ; the orchard oriole, with less orange than the preceding; the large meadow-lark, brownish above and yellow below; the red-winged blackbird ; the cow-bird, which builds no nest but lays its eggs in the nests of various small birds ;
1 Fig. 278.
294
ZOOLOGY
and the " bobolink," as it is called in the North, Avhose song is the merriest of all birds. In the South, whither the bobolink migrates in the winter, it is a great pest in
FIG. 278. — Purple grackle (Quiscalus quisculci).
the rice-fields, and is known as the u rice-bird." It is slaughtered there as a game-bird.
The Corvidae include the crows and their allies, all of them birds of large size. The crow, the raven of the West and of Europe, and the blue jay (Fig. 279) are the com- monest North American species of this family.
THE ENGLISH SPARKOW AND ITS ALLIES 295
The Alaudidae, or larks, are a family chiefly of Old World birds of dull color, building a rough nest on the ground, and feeding on seeds and insects. The skylark of Europe is renowned as a songster. In this country we have one
;' ' A V v
S -T— /
! ' " - f
J U |
FIG. 279. — Blue jay (Cyanocitta cristata).
representative of the family, the horned lark, found also in Europe.
The Tyrannidae, or flycatchers, are an exclusively Ameri- can family, feeding on insects. The best-known represen-
296
ZOOLOGY
tatives are the courageous king-bird (Fig. 280), the wood pewee (Fig. 281), and the water-loving phcebe.
Fi<i. '2X0. — Kingbird
* tt/r<nnitis).
FIG. 'J8L — Nest of pewee. Photo, by D. and S.
THE ENGLISH SPARROW AND ITS ALLIES
We will now pass in brief review the principal Orders of Birds other than Passeres. The Psittaci include the parrots and cockatoos. In the cockatoos the feathers of the head are elevated to form a crest. In the parrots there is no such crest; in one subdivision the tail is long; in a second, very short. The representatives of this
FIG. 282. — Conurus carolinensis, the Carolina paroquet. One-fifth nat. size. After Wilson.
family are found almost exclusively in the tropics, in Brazil, the Moluccas, and in Australia. In general, these birds have a loud voice, and certain species may be trained to articulate words and combine them into sentences. There is only one parrot native to the United States - the Carolina paroquet (Fig. 282j. This formerly occurred
298
ZOOLOGY
north to the Ohio River, but it has been within recent years practically exterminated by plumage hunters.
The Raptores include eagles, hawks, and falcons ; the vultures; condors; and owls. These birds feed chiefly on
FKJ. lifSo. — Sharp-shinned hawk (Ac- cipiter velox) .
FIG. 1^84. — Screech owl (Meya-scoj>s
asio) ,
birds and mammals, which they capture alive in their claws or beaks ; a few live on carrion. They occur in all parts of the globe. The bald eagle, used as a symbol of the Republic, is the commonest of our eagles. Among
THE ENGLISH SPARROW AND ITS ALLIES 299
our hawks, the sparrow-hawk, which is only about the size of the robin, is one of our commonest; others are the sharp-shinned hawk, which kills birds almost ex- clusively, and is especially destructive to poultry,1 and Cooper's hawk, which is also destructive to birds. These two hawks have practically no redeeming qualities, ex- cept the fact that they prey upon the English sparrow. The vultures are represented in our fauna by the turkey-buzzard, which, like other members of the family, feeds on carrion. The European and African vultures even exceed the turkey-buzzard in size. The condor is the largest of the American Raptores. It preys even upon live sheep and calves. The owls, which live in dark holes and feed upon small mammals at night, are found over the globe. Our commonest species is the reddish gray screech-owl.2 The great horned owl is an inhabitant of wooded tracts, and is destructive to poultry and small mammals. The snowy owl is one of the handsomest of all owls, and is frequently seen stuffed in houses in Europe as well as in North America.
The Scansores include the toucans and cuckoos on the one hand and the woodpeckers on the other. The toucans are characterized by an enormous bill, which in extreme
*/
cases is as long as the rest of the bird. It would be ex- tremely heavy were it not filled with air spaces of great extent. These birds inhabit Brazil. The great bills are of use in feeding on fruits. Filling the place in the Old World of the toucans of the New are the hornbills of Africa and Asia, which are likewise frugivorous. The cuckoos are typically represented by the Old World cuckoos. Like our own cow-bird, they have the peculiar
iFig. 283. -Fig. 284.
300
ZOOLOGY
habit of laying their eggs in the nests of other birds, espe- cially insectivorous birds, where they are brooded and the young are fed by the foster-mother. Our native cuckoo, however, broods its own eggs, and is a useful insectivo- rous bird. The kingfishers are also placed in this group.
sjSife^r- > .,-•'
Fm. 2Hf>. — Belted kingfisher (O/-//fc a
They are especially an Old World family, but one genus, Ceryle, has found its way into North America and even into South America. These birds feed chiefly on fish, and they have gained a compact oily plumage to prevent them from getting wet when they plunge for their prey. Our species is known as the belted, kingfisher (Fig. 285).
THE ENGLISH 8PA1U1OW ANT) ITS ALLIES 301
The woodpeckers include for the most part arboreal birds which feed chiefly on insects and have loud, harsh cries. The common idea that they are sap-suckers and destructive to trees seems to be true only of one of our species — the yellow- bellied woodpecker. The heavy, long bill enables woodpeckers to peck holes in trees for wood-eating in- sects, and the long, barbed, protrusible tongue aids in remov- ing the prey. Our commonest woodpeck- ers are the golden- winged woodpecker, or flicker,1 the red-headed woodpecker, the hairy woodpecker, and the d o w n y woodpecker. An interesting ques- tion concerning the golden -winged wood- peckers of the East and Southwest is whether they hybridize where their areas of distribution overlap.
The Cypselomorphae include the humming-birds, swifts, and goat-suckers. The humming-birds are mostly small species, limited to our hemisphere, and characteristic of
Fi(i. 28(i. --Flicker
auratns).
Fig. 286.
302
ZOOLOGY
the tropics. One species, the ruby-throated humming- bird, reaches New England and Canada. These usually
brilliantly colored birds feed on insects and nectar, which they gather from flowers. They fly with great swiftness, nest in trees, and lay only two white eggs (Fig. 287).
The Swifts have a broad gape, and no bristles at the base of the bill. They have habits much like swal- lows, and are found especially in the warm parts of the world.
FKJ- 287. — Ruby-throated humming-bird :. .
(Trochiius coinbris). Most species ot this
family have salivary
FIG. 288. — Nest of chimney-swift. Photo, looking down chimney, by D. and S.
THE ENGLISH HP ARROW AND ITS ALLIES 803
glands, whose secretions aid in cementing the nest. Our
common representative of this group is the chimney-swift,
or chimney-swallow.1 Certain Chinese species make nests
entirely of the mucilaginous secretion of the saliva rv
glands ; these constitute
the edible birds'-nests
of the Chinese. The
goat - suckers include
night-flying birds, with
exceedingly broad gape
and insectivorous habits.
The night - haAvk of
North America, and the
whippoorwill, noted for
itii characteristic night
; '\
cry, are familiar ex- amples.
The order Columbinae includes the pigeons and allies, characteristic of the Eastern Hemisphere. The most interesting species of the group - the dodo and the soli- taire, formerly inhabit- ants of the islands of Mauritius and Rodri- guez, r e s p e c t i v e 1 y - have become extinct within historic times through the settlement of these islands by white men. These birds had rudimentary wings and tail. Their nearest living
FIG. 2S!). — Passenger pigeon (Ectop/sfes migratorius) .
1 Fig. 288.
804
ZOOLOGY
ally seems to be the u maiiu-mea1 " of the Samoan Islands. The pigeons proper are represented in North America by three wild species (Fig. 289). The domesticated pigeon, Columba livia, is a native of southern Europe or western Asia.
The order Gallinacei includes a number of terrestrial birds of large size, especially the grouse or partridges, the pheasants and common fowl, the guinea fowl, and the tur-
FIG. 290. — Ruffed grouse (Bonaxa
keys. On account of their large size and well-flavored flesh, they are much used as human food. The grouse of America include the familiar kb bob-white ' or quail, which is undergoing a rapid extermination in populous regions ; the Canada grouse, which does not occur south of New York; the ruffed grouse of the Eastern States;2 and the prairie chicken of the Great Plains, which has also become almost exterminated. In Europe the large
1 Red-bird.
2 Fig. 290.
THE KXfJLffUf RPAHHOir A.\I) ITS ALLIES 30")
" capercallie v and the blackcock are favorite game-birds. The pheasants are characteristic of southern Asia and China; they comprise some of the most brilliantly colored and greatly ornamented of birds, such as the peacock and the golden pheasant. Here also belong our barnyard fowl, derived from a \vild species, Grallus kmikiva* inhabit- ing northern India, the Hast Indies, and the Philippines. The guinea-fowl is a native of Africa, where it goes in large flocks and is difficult of approach. The turkeys are North American birds. The wild turkey formerly
«/ i/
occurred over all the United States and Mexico. It was first taken to Europe in 1524, was domesticated there, and now occupies much of its former habitat as a domesticated fowl. From this brief view we see that the family of (ial- linacei is, for man at least, one of the most important families of birds.
The Grallatores, or waders, include a great number of shore birds known as plovers, sandpipers, snipes, rails, cranes, herons, and storks. The plovers walk and fly along shore, picking up worms, mollusks, and amphibians; the golden plover and the killdeer are well-known game- birds. The snipes are found in meadows or, less com- monly, in woods. One of the most common is the spotted sandpiper, also called •"• tip-up ' from its rocking move- ments (Fig. 291). It is seen walking around small pools of water by the roadside or in fields. Along the coast are found woodcock and large snipes. Among the herons, our great blue heron attains a length of four feet and is a notable resident of swampy regions; the egrets have been practically exterminated to meet the demands of milliners ; the bittern is still common on tide-flats.
The Natatores, or swimmers, comprise the ducks and
X
306
ZOOLOd Y
geese, the pelicans, the petrels, the gulls and terns, and the divers. Of the geese, the wild goose, or Canada goose, is most commonly seen in its migrations. Of the native ducks we have many kinds, almost all rapidly disappear- ing before the "sportsman." The pelicans are large fish- eating birds, with a huge bag-like lower bill. In this country the white pelican is not uncommon. The large-
Fi<;. 2D1. — Spotted sandpiper (Act it is macularia).
winged petrels follow in the wake of coastal vessels. The terns, which are slender birds with a straight bill,1 were once abundant along our coast, but have been decimated to " ornament" bonnets. The gulls, which are heavier than the terns and have hooked bills, are still abundant over all bodies of water. Finally, the loons are large birds,
1 Fig. 292.
THE ENGLISH SPARROW AND ITS ALLIES 307
powerful fliers and swimmers, which are found in the lakes of the Northern Hemisphere. They are quick divers, and can swim under water for a considerable distance.
The order of Cursores includes the African ostrich, the American ostriches or rheas, the cassowaries of the East Indies, and certain wingless birds of New Zealand (Ap-
Fi(i. l^i)2. — Common tern (titn-ita hirundo).
teryx1). These are regarded as the most lowly developed of the birds ; the vanes of their feathers are not united, but separate to form a sort of hair-like covering to the body. The African ostrich is the largest living bird. It wanders in families or flocks in the deserts of Africa, and feeds on grass, grain, and small animals. It also swallows undigestible matters, such as stones, which probably aid
1 Fie. 293.
SOS
ZOOLOGY
it in triturating its food. The nest consists of a hollow scooped out of the earth, into which about thirty eggs are laid. Ostrich feathers are used for ornament, and so important is the commerce in these articles that ostriches
FIG. 293. — Apteryx australis with egg. From a specimen in the Royal College of Surgeons, London. From Parker and Has well, " Text-book of Zoology."
are extensively farmed in South Africa. When reared in captivity the eggs are hatched in an incubator, and the young carefully fed. The feathers are cut off and not pulled out, so that the operation of gathering the feathers is a painless one.
THE ENGLISH SPARROW A XI) ITS ALLIES 300
Bird Migration. — The birds of any territory may be classified on the basis of their residence into four groups : permanent residents, winter residents, summer residents, and transient visitants. In New York the permanent residents are represented by the screech-owl, the crow, and the gold-finch. Winter visitants are represented by the snow-bird and white-throated sparrow ; summer resi- dents by the wood-thrush, cut-bird, yellow warbler, bobo-
J v
link, and barn-swallow ; transient visitants by most of the warblers, the fox-sparrow, and white-bellied swallow. As
this classification indicates, the bird fauna of any place is, to a great extent, shifting from season to season. In the spring at any latitude many species are seen passing far north, and in the autumn passing south again. Tem- perate as well as southern latitudes receive in the winter time the southern edge of a more northern fauna. Thus Sfeese and ducks are forced by the universal ice of the
O v
Arctic winter to go to regions of open water, at least. Many kinds of birds which spend the winter in the South come North to breed. For example, the bobolink is found nesting in the New England fields in summer, and is then altogether absent in the South. Lithe fall this bird is not
found in New England, but occurs in the Gulf States as
~
the rice-bird. The cause of this migration on the part of birds breeding in the North is the need of food. Insectiv- orous birds, especially, could not obtain food enough in the North in winter.
Migration Routes. — It is known that many species which migrate even great distances travel along well- defined paths. In Europe the paths of the shore migrants have been carefully mapped out. It appears that these birds follow the shore line very exactly, except in some
810 ZOOLOGY
cases in which it can he demonstrated that their paths are along ancient shore lines. As Wallace says : " It is easy to see how the migrations that had once taken place over continuous land would be kept up first over lagoons and marshes, then over a narrow channel, and subsequently over a considerable sea, no one generation of birds ever perceiving any difference in the route." The migration routes of North America have not been well studied. The Atlantic coast is one line ; the Mississippi valley, for- merly, no doubt, an arm of the sea, is another route along which even sea-birds now migrate. The question how birds recognize and are able to follow their migration routes, is a difficult one ; they seem to have a marvellous sense of direction. There is great need of a more perfect knowledge of migration phenomena in North America. Every one who has learned to distinguish accurately the species of birds can contribute to this knowledge by keep- ing records of the time of appearance of migrants in the spring and the fall. The American Ornithologists' Union has for many years solicited observations on this subject from voluntary collaborators.
v
Bird Flight. - The difficulties which must be overcome in order to fit birds for flight are, first, that of sustaining the heavy body in a medium of such low specific gravity as the air and, secondly, that of progression in this medium. To diminish the difficulty of sustaining the body, the specific gravity is reduced to a minimum by great air- spaces in the body, which exist even in the hollow bones. The body is kept from being overturned in the air by the position of the wings, which are placed high up on the trunk while the digestive organs, breastbone, and breast muscles are placed low. To aid locomotion, the general
THE ENGLISH SPARROW AND ITS ALLIES 311
form of the body is made conical, so as to offer little re- sistance to the air, while, by varying the position of the head, wings, and tail, the centre of gravity is quickly shifted. In starting to fly, the bird sftiins an initial veloc-
o «/ * o
ity, if 011 the ground, by springing into the air, or if on a tree, by combining the velocity due to gravity with a push- ing from the limb ; but aquatic birds strike the surface of the water with their wings. The best fliers have relatively large, pointed wings. Three methods of flight are em- ployed by birds when once in the air : («) stroking the air with the wing; (£>) gliding or skimming ; and (c) sailing or soaring. Some birds can use all three methods, and all good fliers use the first two. In the stroke the wing moves downward and forward, backward and upward, so that the tip of the wing describes a QO; and the plane of the wing constantly changes so as to push downward against the air, and thus keep the bird up, and to push backward against the air, and thus drive the bird forward. At the same time, the wing must be brought back to its upper and anterior position without offering great resistance to the air. In gliding, the wings are spread, but are not flapped, - progression depends upon an acquired velocity or upon the wind. In soaring, the wings remain motionless, and the bird does not lose its velocity nor tend to fall. Tne way in which the bird is supported and carried along is uncertain. It seems to depend upon certain favorable currents in the air.
Birds, like insects, have the closest economic relations with man. A few of them, chiefly belonging to the orders of Natatores and Gallinacei, are very important as human food; but most of them concern man on account of their feeding habits, which are either favorable to man, as when
312 ZOOLOGY
noxious insects are destroyed ; or injurious, as when grain- helds are ravaged or other birds are destroyed. Un- questionably the vast majority of birds are commercially advantageous to man. The Kaptores are only partially so, for they feed entirely upon animal food, chiefly birds and small (usually destructive) mammals. The bobolink and the American crow, to be sure, together annually destroy millions of dollars' worth of grain, yet during the breeding season they both feed much upon insects. Outside of the group Kaptores, there are few, if any, completely noxious birds, and even many of the hawks are efficient destroyers of insects. Legislation directed toward the destruction of any kind of birds, excepting the English sparrow and the Cooper's and sharp-shinned hawk, is quite as apt to do harm as good.
Bird Protection. — Travellers in certain parts of Europe, where the poverty and ignorance of the people have led them to prey upon birds, have remarked on the desolation of a birdless country. The natural enemies of insects being destroyed, there is no adequate check to the destruc- tion of vegetation by them and the beauty of a forest landscape is missing. North America has been richly provided witli a native bird fauna ; but within the last few years it has become plain that most of our species are undergoing reduction, and many are near extermination. Careful inquiries recently made indicate that during the past fifteen years the number of our common song-birds has been reduced one-half, and the number of certain birds prized as food or ornament has been reduced to one-fourth. At the present rate, extermination of many species will occur during the lives of most of us. The causes of this destruction of birds are numerous. The most efficient
THE ENGLISH SPAKUOIV AND ITS ALLIES 313
cause is the shotgun in the hands of boys and thoughtless men, and of those who gather birdskins to meet the demand for bonnet "ornaments." Very great destruction is also caused by egg-collectors, who annually gather scores of
FIG. 294. — Hesperornis regalis. The restored skeleton. After Marsh.
thousands of eggs, often of rare birds. The disastrous results of killing birds need only to be appreciated in order to put a stop to this destructiveness.
Extinct Birds. - The destruction of species of birds goes on fast enough without the more efficient aid of man.
314
ZOOLOGY
We know of .species which have become extinct within recent times through the introduction of new enemies among them. Such was the fate of the dodo. Then remains have been preserved to us in the rocks of species which lived in very remote periods. The oldest known fossil bird, Archeeopteryx, of the Jurassic age, had a long tail like a lizard ; but feathers, which are only modified scales, were present even in this oldest known bird. In the Cretaceous rock deposits of the Great Plains there have been found fossil birds with teeth set in sockets or grooves, precisely as they are to-day in reptiles (Fig. 294). These remains show us in the clearest manner that birds have been derived from reptiles. Indeed, the two groups are closely related anatomically, and are often united under the name JSauropsida or lizard-like animals.
APPENDIX TO CHAPTER XIX
KEY TO THE ORDERS OF BIRDS
a\. Sternum with keel for insertion of flying muscles
[Carinatse]. bi. Toes more or less webbed or fringed, legs
used for swimming or wading. Ci. Short legs, broadly webbed [Swimmers] C2. Long legs, long, thin neck, and long beak
[Waders]
62- Feet not webbed, fitted for walking. c\. With cere.
d\. Beak strong, and bent downward at
point ; perching feet ; flat nail (?2- Beak not bent downward at point ; short, cloven feet ; nail com- pressed
Natatores Gmllatnres
Gallinacei
Golumbinw
APPENDIX TO CHAPTER XIX 315
(}$. Beak hooked ; strong, sharp, hooked
claws ...... Raptures
d±. Beak shorter than high ; thick, fleshy
tongue Psittaci
c%. Without cere.
d]_. Beak long, often heavy ; tongue thin ; stiff plumage with little down ; metatarsus with half rings on scutes; feet scansorial . . . Scansores
dz. Metatarsus with no scales or rudi- mentary ones ; feathered in upper part Cypselomorphce
ds- Metatarsus covered with lamina? or scales, rarely feathered, usually with singing apparatus ; feet not scansorial, mostly migratory . Passcres
a-2- Sternum without keel [Ratitas] .... Cursores
KEY TO THE FAMILIES OF PASSERES OF NORTHERN UNITED STATES, BASED OX D. S. JORDAN
«i. First of the 10 primaries more than f length of
longest of the others [Clamatores] . . . Tyraimidce
a*. First of 10 primaries short, rudimentary or ab- sent ; musical apparatus highly developed [Oscines].
b\. First primary short or spurious [primaries 10]. d. Tarsus booted ; rictus with bristles.
d\. Middle toe quite free from inner ; birds of moderate size ; length more than 15 centimetres. e\. Wings when folded not reaching
beyond middle of tail ; no blue Titrdidaz
e-2- Wings reaching beyond middle
of tail ; ours chiefly blue . Saxicolidcu d-2. Middle and inner toe connected at base ; length less than 13 cen- timetres
Cz- Tarsus scutellate in front.
di. Nostrils concealed by bristly feathers.
11(5
ZOOLOGY
€]_. First primary not more than i length of second ; length less than 20 centimetres, /i. Bill as long as head ; wings
longer than tail
./•_'• Hill much shorter than head ;
wings about as long as tail
PZ- First primary more than 1 length
of second; length more than
20 centimetres
•/•:• Nostrils exposed or merely overhung
by feathers. ('i. Bill notched near tip.
J\. Tail longer than wings ; gen- eral color gray or ashy brown.
f/i. Bill very stout and deeply notched and hooked ; bird over 17 centi- metres
f/-j. Bill neither stout, notched, nor hooked ; bird over 17 centimetres </5. Bill very slender ; bird under 17 centimetres . /j. Tail shorter than wings ; gen- eral color olivaceous . ('%. Bill not notched.
J\. Rictus with bristles.
i/ 1. Quills not barred ; length over 20 centimetres . (1-2.. Wing and tail barred ; length under 18 cen- timetres
./•> Rictus without bristles
Firsf primary about as long as second ; the
real lirst rudimentary, leaving apparently 9.
Cj. Bill triangular, depressed, as wide at base
as long ; gape twice as long as culmen
c2. Bill stout, conic, with convex outlines,
Par id a:,
Corrida:
Lioiiidce
Tnrdido:
Tvoglodytidw
Cei'tli iidf.c
Hir«d in idie
APPENDIX TO ('II APT EH XIX
317
edge of upper bill with lobes or nicks near middle .....
Bill conical, corners of mouth drawn
down.
<li. Bill much shorter than head, usually notched at tip or with bristles at rictus ......
(/._.. Bill usually about as long as head ;
no notch at tip nor bristles at rictus
Bill not as above ; edge of upper bill
straight or very gently curved.
d\. Conspicuously crested ; bill trian-
gular, depressed, notched, and
hooked ; tail tipped with yellow ;
wings red-tipped ....
<7o. Nostrils concealed by bristly feath-
ers ; tarsus scutillate behind . (?-. No crest ; nostrils exposed; tarsus with sharp ridge behind formed of union of two lateral plates. e\. Hind claw twice as long as mid- dle claw .....
f>.2. Hind claw not twice as long as
middle claw.
J\. Bill stout, compressed, hooked at tip ; tail not blotched with red or yellow . . /o. Bill various; little, if at all, hooked ; colors often brill- iant .....
T<u><ujri<l<_c
FringillidcB
MotctcilHdcK
Vireonida1
CHAPTER XX
THE MOUSE AND ITS ALLIES
THE mouse belongs to the class Mammalia,1 character- ized by having milk glands whose secretion is used to nourish the young, and hair, which may be nearly or quite absent as in the case of porpoises or whales.2
The distribution of the house mouse, from which the different kinds of fancy mice have been derived, is now co- incident with that of civilized man ; but in early times it was limited to Asia. From Asia it made its way to Europe, and thence by vessels to other continents. It was imported to America (which has no indigenous members of the genus Mus) by the early explorers. There have also been im- ported to this country three other species of this genus, of such size that they are commonly called rats. Of these, the roof rat seems to have been imported by the early Spanish discoverers to the Southern States, where it still persists. It originated in Egypt. The second was the black rat, believed to have been imported to America about 1544. It has existed from time immemorial in Europe : it has a mild disposition, and from it the white rats we keep as pets have been derived. The brown, or Norway rat, has been the latest importation. The history of its migra- tions has been written. Probably originating in central
belonging to the breast.
- A key to the orders of Mammalia will be found in the Appendix to
this Chapter, page 331.
318
THE MOUSE AND ITS ALLIES 319
Asia, it crossed the Volga in great troops in 1727, occupied Russia in 1730, France in 1750, and Denmark about 1810. Before the advance of this powerful and aggressive foe, the black rat of Europe gave way, and became well-nigh exterminated, although of late it is said to be reasserting itself in Germany. The brown rat was introduced into America in 1775, has spread over the whole country, reaching the Paciiic coast about 1855, and, as in Europe, has nearly exterminated the black rat.
The habits of rats and mice are well known. They inhabit our buildings, gnaw our doors and furniture, de- stroy our provisions, kill poultry, and aid in spreading disease. They shun the light, living in holes during the day, run with great agility, and are capable of making long leaps. Owing to their instinct to go into holes, they are easily trapped by a funnel-shaped opening leading into a closed box. Despite the ease of trapping and their destruction by cats, they maintain themselves by virtue of a great fecundity, for, if no deaths occur, several hundred young may, in one year, descend from a single pair.
The food of mice is very varied. They naturally thrive best on a vegetable diet; oats especially are recommended for tame mice, and hard-shelled nuts are useful because the mice keep their teeth sharp by gnawing the shells. If the teeth are not kept worn off they soon become incon- veniently long owing to the fact that they grow continu- ously throughout life, and are not formed, once for all, like our teeth. In addition to plant materials, rats and mice eat a certain amount of animal food.
The different races of tame mice illustrate the results obtained by preserving sports and selecting the best for breeding purposes. The white mouse, for instance, is an
320
ZOOLOU Y
albino ; that is, an animal without pigment. Albinos oc- cur among almost all kinds of mammals, but the cause of them is unknown. So, likewise, the black race of tame mice is due to an excess of pigment, a sport found now and then among other mammals. The pure reddish brown races have probably been produced by selecting the house mice with little black in the fur. By preserving occasional sports and by selecting for breeding the purest-colored individuals, all the different races of our domestic animals and plants have been established and improved.
Other Rodents. — The mouse belongs to the group Ro- dentia,1 distinguished from other mammals by the fact that
Fi<;. 21)5. —
itK (><?</, the Georgia gopher. One-half nat. size. After V. Bailey.
the cutting teeth grow continuously throughout life, a con- dition associated with the habit of gnawing. This group is very abundantly represented in North America, more so, indeed, than in other continents. All our rodents fall into seven families: (1) the squirrels, gophers (Fig. 295), prairie dogs, and wood chuck, with long and hairy tail ; (2 ) the beaver, with broad and scaly tail ; (3) the pouched gophers, with peculiar cheek pouches opening outside the
1 "From roder f, to gnaw.
THE MOUSE AND ITS ALLIES
321
mouth ; (4) the jumping mice, with greatly elongated hind legs; (5) the muskrat and the various wood and field mice, closely related to the genus Mus ; (6) the por- cupines, with bristles replacing hairs ; (7) the hares, with long ears and short tails. All of these familiar rodents are, on the whole, destructive to agriculture. As there are, however, other interests in life than agriculture, it is to be hoped that the warfare against our native rodents will not be too relentlessly pursued. At least one interest- ing species has been rendered well-nigh extinct by the
FIG. 296. — Ortiithorhynctius atiattnus, the duckbill. After Vogt and Specht.
avarice of fur hunters - - this is the American beaver, an animal which has developed extraordinary instincts for the construction of dams and subaquatic passages.
Other Mammals.- The Monotremata1 are the lowest mammals, and in many ways seem to connect the class with reptiles or amphibians. The milk glands are in a
s, single, Tprjua, hole or opening ; so called because urinary, geni- tal, and alimentary canals have a common external opening.
822
ZOOLOGY
low state of development and eggs are laid, as in reptiles and birds. There are two principal types, - - the " Duck- bill' (fig. 296), with aquatic habits, and the "Spiny Ant-eaters' (Echidna, Fig. 297), inhabiting rocky places. Both types are confined to Australia and neighboring islands.
The Marsupialia ! have a remarkable distribution over the earth to-day. All are confined to Australia and adja-
FIG. 297. — Echidna aculeata, the spiny ant-eater. After Vogt and Specht.
cent islands, excepting the family of opossums (Fig. 298), found only in the Americas. There is thus a great dis- continuity in the distribution of marsupials. This is accounted for by the evidence that formerly the whole world contained marsupials, so that those living to-day are the separated remnants of that once universal race. The opossums are most numerous in the tropics, but the Vir- ginian opossum ranges north to New York.
1 marsupitan, a pouch.
THE MOUSE AND ITS ALLIES
323
The Edentata,1 few of which are entirely without teeth, include the sloths, hairy ant-eaters, armadillos, scaly ant- eaters, and aardvarks, or African ant-eaters. The three first-named families inhabit South America ; the two latter, Asia and Africa. Here, again, the discontinuity of the group indicates what fossils prove, that the Edentates
FIG. 298. —
ij* rirgittlana, the North American opossum. After Vogt and Specht.
have been killed off from the connecting continents. The sloths have incisor teeth, live in trees, and eat leaves (Fig. 299). The armadillos are protected by strong plates de- veloped in the skin ; they are chiefly nocturnal and om- nivorous animals, and burrow rapidly. The other three families feed on ants and termites, lack complete teeth (ex- cepting the aardvarks), and are either arboreal or burrowing.
1 e, out ; dens, dent is, tooth.
324
ZOOLOGY
The Cetacea1 have taken to an aquatic life, for it is certain that their ancestors were land animals. The sea- cows (manatees2), found in rivers in various parts of the world, seem8 to show a transition to the marine forms,
FIG. 299. — Choloepus, the unau or two-toed sloth. After Vogt and Specht.
such as the dolphins, the toothed whales (Fig. 300), and the toothless or whalebone whales. The largest of these whales - - the Greenland whale - - reaches an ex- treme length of twenty-two to twenty-four metres, and a
1 cetus, whale. 2 From a native name.
3 The relation to Cetacea is not close.
THE MOUSE AND ITS ALLIES 325
weight of over 100,000 kilogrammes. It is, indeed, the largest living animal. Although whales in general are partly adapted to an aquatic life, they still retain the essential mammalian qualities. They breathe air which passes to the lungs and is expelled again through the nostrils, which are placed high up on the head. The " blowing ' of the whale is the forcible expiration of moisture-laden air, which becomes visible by condensation,
FIG. 300. — Oca, the killer whale. After True.
just as our own breath does on a cold day. The young are doubtless born in the water, but the breeding habits are poorly known. The various Cetacea have diverse feeding habits. All are predaceous. The toothed whales feed on larger animals, the whalebone whales on floating fish, Crustacea, medusae, and squids ; their whalebone is, indeed, merely a strainer to let the water pass out of the mouth while the solid masses are retained.
The order Ungulata1 includes a large number of animals,
1 unyula, hoof.
326
ZOOLOGY
almost all of which are closely related. In the true ungu- lates there are never more than four functional toes ; but in the subgroup of Subungulata, containing the elephants and certain small animals allied to the "coney' of Scripture, there are typically five. Of the true ungulates, we distinguish the even-toed and the odd-toed, which we may consider further.
FIG. .'301. — Stone's Alaskan black sheep. Photo, of a group HI the Field
Columbian Museum.
The Even-toed Ungulates include the hippopotamus and other pigs and the peccaries, the camels and llamas, the deer, the giraffes, and the antelopes, sheep (Fig. 301), and oxen. Excepting the pigs, most of these feed exclusively on plants. The giraffes and antelopes are characteristic of Africa; but the "mountain goat" of our highest ranges is
THE MOUSE AND ITS ALLIES 3*27
a true antelope, as is also the chamois of Europe. The prong-horn of our Southwestern plains is remarkable in having hollow horns like the antelopes, which are, how- ever, shed like those of the deer.
The Odd-toed Ungulates include the horses, tapirs, and rhinoceroses. The horses are remarkable in that they stand upon the toe-nail of the middle digit — all the other digits being rudimentary or absent. While fossil remains of horses are found in all continents, the living species have come from Asia and Africa. The African species are striped (zebras). The tapirs are found living to-day only in South America and southeastern Asia. They frequent the depths of forests near watercourses and feed on leaves and shoots of shrubbery. The rhinoceroses of Africa, of India, of Java, and of the Malay Archipelago are quite distinct. All are large, stupid, and ferocious when attacked, feed on herbage, and wallow in pools.
The elephants are distinguished by their long trunks, great incisors (tusks), and huge, complex grinding teeth. The Indian and African types are quite distinct. Ele- phants are intelligent, tractable, and capable of doing much work for man. Their diet is vegetable, consisting especially of the leaves and young branches of forest trees, which they gather with their proboscis.
The Insectivora1 are small mammals and chiefly terres- trial. One of our common families includes species of moles which burrow in the ground, have small eyes and broad, shovel-shaped fore feet, used for digging their bur- rows. They feed chiefly on earthworms. The other common family is that of the shrews, which are mouse-like, live chiefly on the surface and in the woods, and feed on insects and small crustaceans.
1 insectum, an insect ; vomre, to devour.
328
ZOOLOGY
The Carnivora1 include both land and marine forms. To the first group (Fig. 302) belong the cats (including tigers, lions, leopards, lynx, etc.) ; the civet-cats, mongoose,
FIG. 302. — Felis jubata, the Cheetah or hunting leopard. Photo, of a group,
iu the Field Columbian Museum.
etc. ; the hyenas ; the dogs (including jackals, wolves, and foxes) ; the bears ; the raccoons; and the great/?/ r-bearers, — martens, minks, weasels, badgers and otters, and skunks.
FIG. 303. — Phoca vitulina, the harbor seal. From Parker and Haswell,
" Manual of Zoology."
1 caro, carnis, flesh ; vorare, to devour.
THE MOUSE AND ITS ALLIES 329
Marine Carnivora comprise the seals (Fig. 303), walruses, and sea-lions ; the more valuable of which are disappearing as a result of man's lack of foresight. Altogether, the Car- nivora comprise the most agile, the most intelligent, the most dreadful, and some of the commercially most im- portant of fellow-animals.
The Cheiroptera,1 or bats (Fig. 304), are extraordinarily modified mammals, which, like the birds, seem to have
FIG. 301. — Syuotus, an insectivorous bat. After Vogt and Specht.
penetrated into the air to prey on the flying insects. Not all bats are insectivorous, however, for certain Old World bats feed on fruits. Our commonest species are the little brown bats (with a nearly fuiiess wing), and the red bat (with patches of fur on the wing membrane).
The Primates2 are of interest because we ourselves are placed in this category together with certain other animals that have attained a less lofty station. The lowest Pri- mates are the lemurs, found chiefly in Madagascar. These have an arboreal habit, and feed on fruits, leaves, and
, hand ; irTepov, wing. 2 primus, the first.
330
ZOOLOGY
small birds and insects. Next higher come the American marmosets, the howling monkeys, and the flat-nosed, pre- hensile-tailed American apes ; still higher are the small- nosed, nonprehensile-tailed apes, including the baboons,
FIG. 305. — Simla satyrus, the orang-utan, in breadfruit tree. From a photograph of a group, in the Field Columbian Museum.
mandrills, and macaques. Finally, come the tailless, man- like apes, found exclusively in the Old World- -the gib- bons, orangs (Fig. 305), chimpanzee, and the gorilla. The two latter are nearest to man, but one cannot say one is the nearer. For, while the chimpanzee approaches
THE MOUSE AND ITS ALLIES
331
man more closely in facial appearance and in intelligence, the gorilla is more man-like in the size and complexity of the brain and in its habit of walking on the ground. There is no reason to doubt that man's species came off from the anthropoid apes ; the recent discovery, in Java, of a fossil form (Pithecanthropus erectus) intermediate between man and the man-like apes, is a strong additional piece of evi- dence. This differentiation of man's species probably began in late tertiary times.
<i\.
APPENDIX TO CHAPTEPv XX
KEY TO THE ORDERS OF MAMMALIA
Oviparous; no mam nine developed
Young born prematurely ; reared in marsupium .
Viviparous ; no marsupium.
1>\. Teeth without enamel .
b-2- Teeth with enamel.
c\. Hind limbs absent.
</i. Elbow and wrist move on each other rf2- Fore limbs not flexible Hind limbs present.
(?i. Digits end in hoofs or hoof-like nails Digits end in claws. c\. Without hands or membranes
between digits, /i. Canines absent . fz- Canines large /3. Canines small . Without hands ; membrane be- tween digits .... With hands
Monotrevnata
c2.
Edentata.
Sire nia Ce.tacea
Ungulata
d-2.
Rodentia
<?2.
Cheiroptera Primates
CHAPTER XXI
THE DEVELOPMENT OF THE FROG'S EGG
ALL living matter has the capacity of increasing itself under proper conditions to an almost unlimited extent, the food which animals devour being the material out of which the new living substance is made. This living sub- stance exists in isolated particles, or masses, which we call individual animals or plants. The animal or plant has also at any stage a definite form which is not exactly alike in any two individuals, but is roughly alike inside the "species." Now the number of individuals of any species tends constantly to diminish through death. It is actually maintained by reproduction. Reproduction always takes place in one way ; namely, by a piece of the parent individual being cut off to form a new individual. This piece may be at first almost shapeless or approximately spherical. But as it grows larger it assumes more and more the form and complex structure of the adult. This process of growing into the adult form is development. In most of the more familiar cases development begins with an approximately spherical egg.
In the case of the frog, the egg is between one and two millimetres in diameter. The eggs, which are numerous, are laid in a common jelly and during development float near the surface of the water in which they are laid.
332
THE DEVELOPMENT OF THE FROG'S EGG 333
Effect of Heat and Light on Development. — Eggs devel- oping in normal environments in nature arrive at nearly the same end-result even when the environments are not
J848 MARCH 1lTfi
20J.H 230 25TH
27TH
28TH 31ST
APRIL 4TH 6TH
10TM MAY 22D
AUG. 18T.H
28TH
OCT. 3 1ST
60°FAHR.
ft
MEAN TEMPERATURE
56°FAHR.
53°FAHR.
51°FAHR..
9
FIG. J306. — A chart showing the correlation between the stage of development of the frog on successive days and the temperature at which it has de- veloped. From Higgenhottom.
identical. We gain, in consequence, an impression that development proceeds unaffected by any changes in the outside world. But this is not true. For one thing, the
334 ZOOLOGY
rate at which the development of frogs' eggs proceeds de- pends closely upon the temperature of the water. They develop most rapidly at about 30-32° C. If the tempera- ture is elevated above this point, the rate of development is retarded, and finally ceases at about 40° C. So, likewise, as the temperature is lowered, the development is retarded, until at the temperature of freezing water it ceases (Fig. 306). If the temperature is too high, development may be abnormal, so that a monstrosity is produced.
Light has a less striking effect on the development of the frog. If light is excluded from the developing eggs, they will develop more slowly. The acceleration of development by rather high temperature and by daylight is probably due to a chemical effect of these agents. It indicates that development is a complex chemical process.
Healing and Regeneration. — If the egg of a frog be pricked slightly, there will be a loss of substance and the resulting embryo will be at first abnormal. Later, how- ever, this abnormality will become smoothed over by appropriate development. So, also, if the tail of the developing larva is mutilated, the AVOUIH! will heal and the missing parts will be re-formed. This capacity of the living organism to restore the normal form after mutilation is seen also in man. For if some of the skin be cut away, or even if parts of internal organs are removed, the wounds will not merely heal, but the lost part will regenerate. The remarkable thing is that in regeneration almost exactly that is produced which was lost. Both regenera- tion and healing in the adult are a survival of the same capacity for development which we see in the egg.
Postembryonic Development of the Frog.- -After reach- ing a certain stage of development the embryo frog, called
THE DEVELOPMENT OF THE FROG'S EGG 335
tadpole, begins to develop legs. The hind legs first appear, afterward the fore legs sprout out, and finally the tail begins to wither away, until the form of the four- legged tailless frog (anuran) is fully developed. In the leopard frog, as in the toad, this change of form (jnetamor- phosis) is completed during the first summer, but in case of the bullfrog and green frog the tadpole passes through the winter in the immature state, and does not complete its metamorphosis until the second summer. Conse- quently, it is not uncommon to find quantities of large tadpoles in ponds at the time the ice breaks up in the spring.
Since Amblystoma and Necturus do not lose their tails, the metamorphosis which they undergo is less profound than that of the frog. In Amblystoma, as stated in Chap- ter XVII., the gills and the fin on the tail of the tadpole are lost in the metamorphosis. Necturus, on the con- trary, retains gills and tail-fin, so that its acquisition of legs is almost the sole indication of metamorphosis.
General Laws of Development. — Development consists of an unfolding of potentialities wrapped up in the germ ; an awakening in orderly succession of processes lying dormant there. But the causes which control develop- ment, the causes which determine when this process and that shall awaken, are still too obscure for us to attempt to picture them in detail. This much is certain, that the causes of development from the egg are the same as those of budding of leaves on a tree, the regeneration of the parts of a Hydra, or the healing of a cut in the skin. In the case of most of the higher plants and animals, the ripe egg will not develop until it is " fertilized," that is, until a germ from another individual has fused with the ripe egg.
336 ZOOLOGY
But the ripe egg of many of the lower plants and animals requires no fertilization for development, and the meaning of the fertilization process is quite obscure.
The developing eggs of all the higher animals pass through much the same sort of early stages. The egg " cleaves ' into a number of cleavage spheres, each of which is destined to give rise to a particular part of the organism. By repeated division, a mass of small cells, constituting the morula stage, is formed. Usually a cavity arises in the middle of the morula, and into this some of the surface cells are pushed to form an internal sac - - the food canal. This is necessarily an early step, as all food is taken into the interior of the body. The pro- cess by which external cells are pushed in is known as gastrulation. Very early the body is seen to be composed mostly of layers, or membranes and cavities. It is by the folding and union and breaking through of these mem- branes that most of the organs of the adult arise. Devel- opment of the individual is, on the whole, accompanied by increase in complexity. The evolution of animals in the animal kingdom is likewise, on the whole, accompanied by increase in complexity of organization. Thus both the embryonic development of the individual and the evolu- tion of the species proceed from simple to complex, and since they start from about the same point and reach the same goal, we are not surprised to find that the individual development of any species often goes through stages markedly like the stages in the evolution of the species. The parallelism of development and evolution was early noticed, and is often called " von Baer's law," after a naturalist who lived in the middle of the nineteenth cen- tury and very clearly formulated this parallelism.
APPENDIX I
NOTE.— This outline is reprinted, with some changes suggested by patting it in practice, and ivith the addition of Exercise XX., from an " Outline of Requirements in Zoology intended for use in preparing students for the Lawrence Scientific School," Harvard University, published in 1898 by the University. The outline was the product of the Zoological Department of the University, iv ax planned in detail by one of the 2) resent writers, and is republished by permission of the University. The outline agrees also with the requirements for admission in Zoology to the University of Chi- cago, and ivith the recommendations of the" sub-committee of ten on Zoology appointed by the National Educational Association. Its general plan has been followed in various schools over the country. The favor- able reception of the outline justifies its reproduction here.
OUTLINE OF LABORATORY WORK IN ZOOLOGY
INTRODUCTION1
Time. — This outline of work in Zoology is designed for use in schools that can give to the subject five periods per week for half a year, including time spent in laboratory work, written exercises, and oral instruction by the teacher. It is likewise available for schools that follow the recommendation of the Committee of Ten of the National Educational Association and give to the subject three periods per week throughout the year.
Amount of ivork. — The outline includes much more work than any school ought to attempt in the time indicated above. It is believed that if about ten of the twenty-one exercises are thoroughly done, the time will be well filled. The number of exercises is made large to admit of a selection to suit the diverse conditions of schools. Thus, those schools which are not equipped with compound micro-
1 Certain verbal changes have been made in reprinting the Introduction, a few sentences ha\ve been omitted, and there are certain additions, which are enclosed in brackets.
z 337
338 ZOOLOGY
scopes will, nevertheless, be able to select from nineteen exercises, while those which in addition are unable to make use of living marine animals will still have a choice from seventeen exercises. A thorough study of a few types, rather than a more superficial study of many, should be aimed at.
General aim. - - It is the general aim of these exercises to interest as well as to train the pupil ; indeed, it is believed that the awakening of interest is the best preliminary and accompaniment to a useful mental training. Since young persons are especially interested in living animals, observations and non-injurious experiments upon the normal reactions and the methods of locomotion of animals are required in nearly every exercise. While the study of active animals will entail much additional labor on the part of the teacher, and some additional expense, it is believed that the results will justify the cost. In order to carry out the aim of these exercises, it is desir- able that the student find answers to his questions, as far as practi- cable, from the object before him, rather than from the teacher or from books. Questions involving comparisons between the types have been omitted, not because they are regarded as unimportant, but because they would necessarily vary according to the particular types selected and the order in which these types are studied. How- ever, the necessity which compels their omission is the less to be regretted, since it leaves the teacher free to exercise his owrn judg- ment and experience in this matter, but he should not fail to supply such questions.
Sequence of exercises. — The sequence of exercises must depend largely upon availability of material ; but it is desirable that closely related types should be studied in immediate succession to facilitate comparisons. The following are suggested for courses occupying different periods in the year : —
LABORATORY WORK
339
Whole Year. |
First Half. |
Second Half. |
I. Grasshopper |
I. Grasshopper |
VII. Crayfish |
II. Butterfly |
II. Butterfly |
VIII. Daphnia |
III. Beetle |
III. Beetle |
XIV. Hydra |
IV. Fly |
IV. Fly |
XV. Paramecium |
XIII. Starfish |
XIII. Starfish |
XL Slug |
X. Nereis |
X. Nereis |
XII. Anodonta or |
IX. Earthworm |
IX. Earthworm |
Unio |
VI. Spider |
VI. Spicier |
IX. Earthworm |
V. Lithobius |
V. Lithobius |
X. Nereis |
VII. Crayfish |
XVII. Newt |
VI. Spider |
VIII. Daphnia |
XVIII. Lizard |
V. Lithobius |
XI. Slug |
XVI. Smelt |
IV. Fly |
XII. AnodontaorUnio |
XIX. Sparrow |
III. Beetle |
XIV. Hydra |
XX. Mouse |
XVII. Newt |
XV. Paramecium |
XL Slug |
XXL Frog's Egg |
XXI. Frog's Egg |
XII. Anodonta or |
XVI. Smelt |
XVI. Smelt |
Unio |
XVIII. Lizard |
XVII. Newt |
VII. Crayfish |
XIX. Sparrow |
XVIII. Lizard |
VIII. Daphnia |
XX. Mouse |
XIX. Sparrow |
XIV. Hydra |
XIII. Starfish |
XX. Mouse |
XV. Paramecium |
II. Butterfly |
Equipment. — A well-lighted laboratory provided with tables is almost necessary, but the teacher may find it possible, with much additional work and less satisfactory results, to conduct the exercises at the students' ordinary desks. The apparatus required will depend upon the exercises selected. In any case there will be needed at least one large aquarium. For this purpose battery jars twelve inches in diameter will be found serviceable. For keeping living insects, cages made of wire netting, placed over food plants growing in broad " seed-pans," are recommended. An ingenious teacher will be able to make many cheap substitutions for some of the apparatus specified. Thus in place of " Stencler dishes " tumblers may be used.
Laboratory book's. — The drawings should be made on a good
340 ZOOLOGY
quality of drawing paper. Tablets made of un glazed drawing paper, about eight inches by ten inches, are recommended.1 "Where loose sheets are employed they must be bound at the end of the course. The drawings should be made with pencil of a hardness (HIIH or HHHH) appropriate to the paper, and kept well sharpened. The use of colored crayons or water colors is to be discouraged. Few pupils can employ shading to advantage. Students are to be in- structed that pencil lines should represent boundaries of structures. The names of the parts represented must be designated and should be the simplest applicable.
Records of experiments, answers to " Questions on External Anatomy," comparisons drawn, and other written exercises should be brief. They should not be made upon the same sheets with the drawings, but either in a separate note-book or on sheets of the same size as the drawing sheets and eventually bound up with them.2
Observations on the living animal. — The experiments upon living animals, especially such as involve reactions to stimuli, should be repeated two or three times, since the first response of the animal may be abnormal or irregular.
Topics for further study. — Under this heading there are given in each exercise suggestions for oral instruction by the teacher, or for reading and recitation on the part of the pupil, in connection with the laboratory work on the type. The teacher will find aid from the larger text-books, encyclopaedias, systematic works, and compendia of Natural History. [The accompanying text-book is fitted especially to these Topics.]
Excursions. — The teacher is urged to undertake, so far as prac- ticable, excursions with his pupils to localities where the organisms studied in the laboratory and their allies can be seen in their natural environment. The student should be encouraged to collect and study insects, mollusks, and other invertebrates, and to make observations on their habits. Directions for collecting various kinds of animals
1 [Boyer's Science Tablets, made by the Central School Supply Company, Chicago, are convenient.]
2 The Harvard requirement says: The laboratory work should be done under the immediate supervision of the teacher, so that he can certify that the drawings and written work are the pupil's own.
LABORATORY WORK 341
are given in the Bulletin of the U. S. National Museum, No. 39. Parts A to M, 1891-1899 are already published.
Material. - - The teacher should know before beginning the course which of the types he can obtain alive in his locality, and where and in what months they can most readily be found. He should know these things not only about the ten types selected but also about others, as certain types may prove to be unobtainable when wanted. He must give due attention to the difficulty of procuring living material during cold weather. Pupils should be encouraged, where practicable, to aid in procuring material for class work ; the excur- sions recommended may be utilized to some extent for this purpose.
Correspondence from teachers who, as a result of their experiences in using this outline, have any suggestions to offer which may be incorporated in a future revision of it, is solicited.
[Dealers in animals for class work. — Mr. George K. Cherrie, Brooklyn Institute Museum, Eastern Parkway and Washington Avenue, Brooklyn, N. Y., will undertake, after September 1, 1900, to supply schools with the animal material illustrative of most of the families referred to in the text, and will supply schools and colleges with preserved animals in quantity for class use.
Dealers in live animals are : —
Mr. C. J. Maynard, 447 Crafts Street, West Newton, Mass.
Mr. F. G. Hillman, New Bedford, Mass.
Aquarium Supply Co., Delair, N. J.
Messrs. C. E. Blake, 1486 E. 69th Street, Chicago, 111. (can furnish some of the material alive).
In addition to the foregoing, preserved material will be supplied by : —
The Marine Biological Laboratory, Woods Holl, Mass.
Messrs. II. H. & C. S. Brimley, Raleigh, N. C. (also some living material).
Mr. F. W. Wamsley, Acad. Nat. Sci., Philadelphia.
Most of these dealers will furnish catalogues of material on application.]
342 ZOOLOGY
EXERCISES I. GRASSHOPPER (Caloptenus femur-rubrum}
Caloptenus (which may be replaced by any other member of the Acrididae or by a cricket) can be obtained abundantly in the autumn.
DRAWINGS
1. Entire animal, left side, wings in place, x 2.
2. Front view of head, x 4.
3. Posterior view of antenna and first and third legs of right side drawn, for comparison, one below the other, x 3.
4. Upper surface of right wings. Draw a vertical line representing the axis of the body, mark the anterior (yl) and posterior (P) ends of the line, and draw the wings one behind the other to the right of this line, x 3.
5. Lateral view of trunk (left side), with legs and wings removed, x 3.
6. Mouth-parts, arrange in a column as in No. 4. x 5.
7. Compound eye (hand lens), x 10.
QUESTIONS ON EXTERNAL ANATOMY
1. Is the number of trunk segments constant? (Count segments of three or more individuals.)
2. Is the number of segments in the leg constant in the correspond- ing legs of three individuals; in all the legs of the same individual?
3. Describe in not over one hundred words the difference between the oldest and the youngest individual you have, in respect to («) size of trunk ; (I) size of wings ; and (c) other characters.
OBSERVATIONS ox THE LIVING ANIMAL
1. Note the respiratory movements of the abdomen. Count the number per minute. Does the number vary with the individual V Does it vary with external conditions such as temperature and stimu- lation ?
2. Holding the grasshopper in the right hand, with the left put the tip of a blade of green grass to the mouth. Note the movements.
LABORATORY WORK, II 343
How does the grasshopper react to different substances on the end of the grass blade ?
3. Place the grasshopper under a bell-glass and note and record the position of the legs in successive phases of walking.
TOPICS FOR FURTHER STUDY
1. Habitat and food of the grasshopper. 2. Distribution of the species studied. 3. Development (general and external). 4. Allies of the grasshopper: cricket, green locusts, walking-sticks, Mantis, cockroaches, earwigs, dragon-flies, ephemerids, termites, the Neurop- tera, Hemiptera, and Homoptera.
II. BUTTERFLY
Any one of various species whose larvae can be obtained alive near the end of September may be employed. The cabbage butterfly (Pieris), the milkweed butterfly (Danais),or the swallow-tail butterfly (Papilio) will meet these conditions.
DRAWINGS
1. Imago : Dorsal view, wings expanded, x 1 or 2.
2. Imago : Left side, wings closed. (The bodies in 1 and 2 are to be drawn parallel to each other.) x 1 or 2.
3. Imago : Front of head, x 10.
4. Pupa : Left side.
5. Full-grown larva : Dorsal view.
6. Full-grown larva : Left side.
QUESTIONS ON EXTERNAL ANATOMY
1. How many segments behind the head in (</) the imago? (5) the larva? (c) the pupa?
2. What external organs of the imago can be identified in the
o o
pupa ?
3. Which feet of the larva correspond to those of the imago ?
OBSERVATIONS ON THE LIVING LARVA
Each student (or group of students) should be provided with a glass vessel covered with netting and containing food leaves for keep- ing the larva during pupation.
344 ZOOLOGY
1. How is locomotion effected? Illustrate by diagrams.
2. How does the larva feed? Observe and record the movements of the month-parts and of the head during feeding. Draw the outline of a partly eaten leaf.
3. (This obsercafion must extend through several days.} Make and record observations upon the act of pupation.
TOPICS FOR FURTHER STUDY
1. The habits and food of butterflies. 2. The number of broods of butterflies during a single season and seasonal dimorphism. 3. Pro- tective resemblance and mimicry. 4. The larger divisions and com- moner native forms of Lepidoptera. (Examples of Lepidoptera illustrating the commoner native types should be shown and students encouraged to collect and classify them.) 5. The Hymenoptera : their structure, classification, and habits.
III. BEETLE
The May-beetle and the potato-beetle are recommended for studies from alcoholic specimens. If these are not available for the " Obser- vations on the Living Animal," any other slow-creeping species may be employed.
DRAWINGS
(From alcoholic specimens}
1. Dorsal view, naming parts, x 8.
2. Remove the antenna, mandible, maxillae, and legs of right side. Draw posterior view of each part. Use lens, x 15.
3. Remove the wing case and membranous wing from left side. Draw wing (a) folded, (/;) unfolded, indicating position of creases. Draw imaginary cross-section of the folded wing.
4. Draw beetle from left side, indicating position of removed wings, x 8.
5. (Optional.} Draw larva from left side, x 8.
QUESTIONS ON EXTERNAL ANATOMY
1. How many segments has the beetle behind the head?
2. (Optional.} How many segments has the larva?
LABORATORY WORK, IV 345
3. From which segments do the wings arise? The legs?
4. Of how many segments is each foot composed ?
OBSERVATIONS ON THE LIVING ANIMAL
1. Place a beetle upon a piece of white paper; observe the order of movement of the legs in locomotion, and record by some graphic method.1 Analyze the movement of a leg of each pair; how does it help the animal to move? Compare with grasshopper.
2. Placing a bit of potato leaf (or other green leaf) at the mouth of the beetle, notice the movements of the mouth-parts in feeding.
3. Observe and record the movements of the feet of the larva in locomotion.
TOPICS FOR FURTHER STUDY
1. Stages in the development of a beetle. 2. The principal classes of beetles : illustrate, e.g., runners, divers, short-wings or rove-beetles, carrion-beetles, wool-beetles, stag-beetles, tumble-bugs, May-beetles, boring beetles, snappers,4 fireflies, bark-beetles, weevils, buck-bee- tles, leaf eaters, ladybirds. (Examples of these should be shown and students encouraged to collect and classify them.) 3. The food of beetles. 4. Economic importance: (a) injurious beetles — destructive to vegetation, to wood, to grain, to meat, to fur and cloth, to useful animals ; (//) useful beetles — advantageous by acting as scavengers, by killing injurious insects.
IV. HOUSE-FLY OR BLUEBOTTLE FLY (Musca domestica
and ]\I. vomitorid)
To get larvae of the bluebottle fly it is only necessary to expose flesh, even on a warm winter day, a week or so before the larvae are needed for class work. The larvae may be fed upon bran, and when well grown may be prevented from pupating by being kept at a tem- perature slightly above the freezing-point.
1 An excellent method, proposed by Professor F. E. Lloyd of Teachers' College, New York, is to have the beetle walk from an anilin ink pad (ordi- nary stamping pad) to the paper. The ink on the feet will leave a print of the steps on the paper.
346 ZOOLOGY
DRAWINGS
1. Imago, dorsal view, wings in place, x 10.
2. Left side, showing stigmata ; wings having been removed and preserved for further study, x 10.
3. Front view of head, with antennae (lens), x 15.
4. Posterior view of first pair of legs, x 15.
5. Dorsal view of wing and balancer of the right side, x 15.
6. Abdomen, ventral aspect, x 10.
7. (Optional.) Egg of fly. x 10.
8. (Optional.) Larva, side view, x 7.
QUESTIONS ON EXTERNAL ANATOMY
1. How many body-segments has the fly behind the head?
2. How many segments in the antenna?
3. How many segments in the leg ? (Compare with grasshopper.)
4. Can you detect any difference between different individuals of the same species in respect to form of the head and eyes ?
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with the following: (1) a bell- jar (or any broad glass vessel) containing a fly and covered with a card; (2) a soup-plate ; (3) vials of various colored, pungent, sweet, and neutral substances, such as white sugar, vinegar, butter (prefer- ably rancid), ground gypsum, white sugar reddened with carmine, |% acetic acid, molasses.
1. Place on the soup-plate at a little distance apart some sugar, a drop of vinegar, grains of sugar, and a drop of water. Invert the bell-jar containing a fly, over the soup-plate, and carefully move the bell-jar until it covers all of the substances. Xote all the movements of the fly for five minutes --these are the instinctive movements of the fly in the given situation; note especially its movements with refer- ence to the substances.
2. Try the same fly with other combinations such as vinegar, mo- lasses, water.
3. Try a second fly with one of the same combinations of substances.
LABORATORY WORK, V 347
QUESTIONS
By what substances are the flies most attracted? What is the par- ticular quality which seems to attract? What sense (sight, smell, or other) seems to have most influence?
TOPICS FOR FURTHER STUDY
1. The habitat and food of the fly. 2. Development. 3. Respira- tion. 4. The parasites of the fly. 5. Other Diptera : Glossina (tsetse-fly), bot-flies, Syrphus, horse-fly, black-fly, crane-flies, gall gnats, gnats, mosquitoes, sheep-ticks or lice-flies, fleas, and jiggers. 6. The economic importance of Diptera as parasites on animals and plants, as gall producers, as destroyers of grain, as distributers of disease, and as scavengers.
V. L1THOBIUS
This myriapod may be obtained under woodpiles, or damp leaves in woods, even in late autumn or during mild days in winter.
DRAWINGS
1. Dorsal view, x 5.
2. Head, under side, naming principal parts, e.g. antennae, jaws, first trunk appendages, etc. x 15.
3. Head, upper side. x 15.
4. Two consecutive segments seen from left side, showing legs and stigma, x 10.
QUESTIONS ON EXTERNAL ANATOMY
1. How many segments in the body? Is the number constant? (Examine two or three individuals.) Are new segments formed throughout life ? Compare with earthworm.
2. How many segments in the antenna? Is this number constant?
3. How many segments in the leg?
OBSERVATIONS ox THE LIVING ANIMAL
Each student should be provided with the following: (1) a glass rod as in No. VI. or toothpicks; (2) vial of cologne; (3) vial of 2% acetic acid; (4) a soup-plate; (5) a pane of glass large enough to cover the plate ; (6) forceps to hold Lithobius.
348 ZOOLOGY
1. Study the movement of a single leg and draw three of its phases. The Lithobius is held in the covered plate.1
2. Make a diagram exhibiting the coordination of leg movement.
3. Touch the antenna with a needle. Response ?
4. Bring a clean glass rod near to an antenna ; then the rod dipped in cologne ; then cleaned and dipped in acetic acid. Record results and conclusions.
5. Does Lithobius tend to move from or toward the source of light?
6. Place on a piece of filter paper, one-half wet and one-half dry, and note reaction at edge of wet part.
TOPICS FOR FURTHER STUDY
1. Habitat and food of chilopods in general. 2. Distribution of Lithobius. 3. Allies of Lithobius : Scutigera, Scolopendra, Geophilus, Polydesmus, Julus ; their habitats.
VI. SPIDER (Argwpe and Theridium}
The large black and yellow garden spider (Argiope) should be obtained in the fall and preserved in alcohol. The house cobweb spider (Theridium) can be obtained alive throughout the year in un- swept corners, especially in cellars. Despite its small size it will serve for the studies on activities. It may be kept in a 4-inch battery jar where it will spin its web. Feed upon flies, plant-lice, and other insects. Other spiders may be substituted for these.
DRAWINGS (of A rgiope)
1. Ventral view showing appendages, opening to air sacs, and spin- ning glands, x 5.
2. Side view (left), x 5.
3. Front dorsal view of head, showing eyes and jaws (hand lens), x 10.
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with the following : (1) a glass rod about 10 cm. long and 2 mm. in diameter, or toothpicks ; (2) a
lrThe movements of the animal may be reduced by adding a little ether, or by holding the body with a forceps.
LABORATORY WORK, VII 349
vial of essence of heliotrope ; (3) a vial of cologne ; (4) a vial of di- lute ammonia; (5) a glass-covered box about 8 inches cube.
1. Offer to the spider the end of the glass rod, first clean, then dipped in essence of heliotrope ; cleaned and dipped in cologne ; in ammonia. Note and record movements.
2. Place the spider in the box and note for ten minutes its instinc- tive movements.
3. Leave the spider in the box for a day or two and draw the web ; in successive stages of formation if possible.
TOPICS FOR FURTHER STUDY
1. Habitat and food of Argiope and Theridium. 2. Distribution of these spielers. 3. Spinning habits of spiders in general: forms of webs and nests of the different classes of spiders ; economic impor- tance of spiders' webs. 4. Biting and poisonous spiders.
VII. CRAYFISH (Cambarus)
Crayfish can be obtained from small streams in most parts of the United States, except New England. They are also for sale in the markets of large cities, and are easily transported and kept alive for days in damp moss. They may eventually be transferred to an aquarium containing water not more than an inch deep. Feed upon earthworms or pieces of meat. The crayfish may be replaced by the lobster.
DRAWINGS
1. View from left side, taking care to preserve accurately the pro- portions, x 1.5.
2. Ventral view. (Omitting legs.) x 1.5.
3. Draw the posterior aspect of the following appendages of the right side of animal, without removal from body, x 2.
(a) small antenna. (g) 4th thoracic appendage.
(&) large antenna. (//) 5th thoracic appendage.
(c) mandible. (i) 8th (last) thoracic appendage.
(c/) 1st maxilla. (&) 4th abdominal appendage
(e) 2d maxilliped. (swimineret).
(/) 3d maxilliped. (/) last abdominal appendage.
350 ZOOLOGY
4. Draw right side of thorax (carapace previously removed) to show the number and position of gills, x 2.
5. Draw dorsal aspect of eye-stalk, x 4.
QUESTIONS ON EXTERNAL ANATOMY
1. How many segments in the last thoracic appendage? Xumber the segments upon your drawing, beginning at the proximal (attached) end. Number as far as you can the homologous segments upon the other thoracic appendages drawn.
2. How can you homologize1 with one another the swimmerets, the legs, and the mouth parts ? Give evidence for each step and indicate results on the drawings already made.
3. Which is the least differentiated of the series of appendages?2
4. What is the gill formula of the animal in hand?
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with the following: (1) soup- plate; (2) needle; (3) vial of dilute ammonia; (4) vial of 5% acetic acid ; (5) vial of carmine.
1. Hold a living crayfish in a soup-plate of water so that the free edge of its carapace is near the surface. Put a few drops of the carmine into the water in front of the thorax ; behind the thorax ; between the legs. Draw a diagram showing the currents. What is the use of these currents, and by what mechanism are they produced?
2. Hold the living crayfish so that its head and anterior half only of thorax are submerged ; observe what takes place at hinder edge of carapace. Hold the crayfish so that abdomen and posterior half only of carapace are submerged ; what takes place at anterior edge of cara- pace ? Interpretation ?
3. Determine the function of each pair of legs used in locomotion and the correlation in their movements.
1 The idea of homology should be made clear. The pupil should indicate the protopodite (/>), exopodite (ex), and endopodite (en) upon all the drawings of appendages.
2 The teacher should make use of the crayfish to explain the principle that different organs have a different degree of specialization or " differentiation." This will lead to the topic of Division of Labor, as indicated below.
LABORATORY WORK, VIII 351
4. To the tip of one of the large antennre and to the small antennae apply (a) the point of a needle; (J>) the vapor of ammonia; (c) a drop of water; (//) a drop of 5% acetic acid. Tests («) and (/;) should be performed upon the antenna of one side and («), (e), and (//) upon that of the other. Record the results. What inferences do you draw ?
5. Wave the hand over the crayfish. Does it react ? If possible flash a light at its head. Can the crayfish see? Cover the eye-stalks with wax. Does it still react to a movement of the hand?
TOPICS FOR FURTHER STUDY
1. The habitat and food of the crayfish. 2. The geographical dis- tribution of crayfishes. 3. Other stalk-eyed Crustacea (long and short tailed) ; lobsters, shrimps, hermit-crabs, spider-crabs, edible crabs. 4. Economic importance of stalk-eyed Crustacea. 5. The breeding habits and general development of crayfish and lobster. 6. The capacity for regeneration in the higher Crustacea and the occurrence of monstrosities. 7. Division of labor in the appendages of the cray- fish.
VIII. DAPHNIA
Daphnia may be obtained from pools at almost any time of the year except midwinter. They may be reared in large numbers in aquaria properly stocked with decaying plants, upon which they feed. Select for class work the largest individuals (females), which may attain a
length of 2 mm.
DRAWING
Place a living animal on a slide under a cover-glass, and with the aid of the simple microscope draw a side view, x 20.
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with the following : (1) Stender dish ; (2) pipette ; (3) watch-glass containing Daphnias ; (4) three pieces of glass tubing 20 cm. long and 4 mm. bore, with two corks to fit.
1. Place a Daphnia in the straight glass tube (6) filled with clear water and corked at both ends. (Exclude air-bubbles in corking.) Place parallel to the rays from the source of light (preferably lamp
352 ZOOLOGY
light) and cut off side lights. Observe and record movements or lack of movements.
2. Place a Daphnia in a tube containing a single wad of algse; place another Daphnia in a tube containing a small pebble ; observe and record behavior with reference to the foreign body.
3. (Optional.) Place an egg-bearing female in a Stender dish con- taining bits of decaying plant. After seven days count the number of individuals. Compare with the number in a similar dish kept (by the teacher) for seven days in a cool place (5° to 10° C.).
TOPICS FOR FURTHER STUDY
1. The habitat and food of Daphnia. 2. Allies of Daphnia: Bran- chipus, Cyclops, Cypridopsis, barnacles, trilobites. 3. The pupil should learn to distinguish Daphnia, Cyclops, and the other Entomostraca in the aquarium by their locomotion.
IX. EARTHWORM (Allololoplwra or Luminous)
Various species may be used. During the winter time, when the ground is frozen, earthworms are best sought under compost heaps; or they may be kept in laboratory in flower-pots containing rich, moist vegetable mould and covered by a glass plate. They may be fed upon fallen leaves placed in the pots.
DRAWINGS
(From alcoholic specimens)
1. Whole animal, dorsal view, x 2.
2. Head end, 6 or 8 segments, ventral view, x 5.
3. Tail end, 6 or 8 segments, ventral view, x 5.
4. Two adjacent middle segments, showing setse. x 5.
5. Cross-section, showing position of setae, x 5.
QUESTIONS ON EXTERNAL ANATOMY
1. Count the number of segments of two or three individuals. Are they the same? Inference to be drawn from the result?
2. Where does growth in length take place? Evidence for your conclusion ?
LABORATORY WORK, X 353
OBSERVATIONS ON THE LIVING ANIMAL.
Each student should be provided with the following : (1) plate cov- ered with moist filter paper; (2) hand lens; (3-5) vials containing sugar solution, acetic acid, and beef extract; (G) four new toothpicks ; (7) pipette.
1. Touch with a toothpick, first the head end, then the tail end of the worm ; to which contact does it react more strongly ?
2. Place the earthworm near the window. Does it move toward or from the light ?
3. With the breath blow upon the head end of the worm. Record results. Are results due to the warmth of the breath or to the current of air ? To test, send a puff upon the head with a pipette.
4. Bring near to the head end in succession the ends of toothpicks dipped in water, in sugar solution, in acetic acid, and in beef extract. How does the worm react to each fluid ?
5. Place the earthworm on a piece of filter paper two-thirds of which is wet. Reaction of worm at edge of wet part ? How do these reac- tions of the earthworm accord with its ordinary movements out of doors ?
6. When the head end is being thrust out forward, in what phase (contraction or expansion) is the middle of the worm? The tail end? In what direction does the contraction wave pass?
TOPICS FOR FURTHER STUDY
1. Habitat and food of the earthworm. 2. Economic importance of earthworms. 3. Allies of the earthworm : Nais, Dero, Tubifex, the leeches, the Gephyrea, the Bryozoa.
X. NEREIS
Nereis can be obtained at the sea-shore by digging in mud flats between tide lines. It can be transported in damp sand or seaweed, and will remain alive for several davs in a shallow vessel filled with
\j
sea-water and kept in a cool place.
DRAWINGS
(From alcoholic specimens) 1. Whole animal, dorsal view. Natural size. 2 A
o
54 ZOOLOGY
2. Head end, dorsal view, x 5.
3. Tail end, dorsal view, x 5.
4. Two adjacent middle segments, dorsal view, x 5.
5. Posterior aspect of a single middle segment, showing parapodia. x 8.
QUESTIONS ON EXTERNAL ANATOMY
1. Which segments are most specialized?
2. Does the number of segments increase during life? Compare several worms.
3. Which segments are last formed in the individual's development ?
OBSERVATIONS ON THE LIVING ANIMAL
(TW persons may work together upon a single Nereis.') Each stu- dent should be provided with the following: (1) hand lens; (2) needle ; (3, 4) vials containing 5% sugar solution and 5% acetic acid ; (5) pipette.
1. How is locomotion accomplished by Nereis? Analyze the move- ments involved in locomotion. Relation of phases of writhe to phases of stroke and recovery of fin. Form of fin at various phases of its movement. Indicate by diagrams the relations which you discover.
2. Touch the head with a needle ; what movements ? The tail ; what movements? What faculty in Nereis is indicated by the changes of movement after contact ?
3. Drop quietly, by means of a pipette, sea-water upon the head end and the middle of Nereis; repeat with acetic acid; with sugar solu- tion. What difference in the movements? What faculty in Nereis is indicated by these differences in movement ?
TOPICS FOR FURTHER STUDY
1. Habitat and food of Nereis. 2. Its distribution. 3. Its allies : Autolytus, Lepidonotus, Amphitrite, Serpula, etc. 4. The round worms and flat worms.
XL SLUG (Umax)
Slugs may be found during the winter in greenhouses and during the spring and autumn in gardens and orchards, under boards and stones. They may be kept for considerable periods in a box whose
LABORATORY WORK, XI 355
bottom is covered with damp moss ; they may be fed upon fresh apples, cabbage leaves, etc. Llmax majcimus is to be preferred on account of its large size.
DRAWINGS (From tJie living individual)
1. Dorsal view, showing mantle, foot, respiratory opening, head and tentacles, x 1.5 to 3.
2. View of right side, x 1.5 to 3.
3. Front view, showing tentacles, mouth, and lips of slime-gland, x 3.
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with a pane of glass, 8 by 10 inches.
1. Place the slug on the glass and study its locomotion from the under side of the plate. Describe in the note-book what is seen.
2. Place the slug on the glass plate, hold the plate vertical and parallel to the window, the slug being horizontal and parallel to one edge of the pane ; shield from lateral lights. Having made in the note-book an outline to represent the plate, indicate in this the posi- tion of the slug at the beginning of the experiment and at intervals of ten seconds for about a minute. Repeat. A piece of planed board is better than the glass plate, excepting that it cannot be kept so clean.
3. Place the plate horizontal near a window and let the slug be par- allel to the window. Do not let direct sunlight fall upon it. Plot in the note-book, as before, the position of the axis of the slug at inter- vals of ten seconds o Repeat.
4. Note the reaction of the slug to contact on different parts of the body : tail, head, antenn?e, edge of mantle.
5. Does the slug react to passes of the hand ? To moisture ?
TOPICS FOR FURTHER STUDY
1. The habitat, food, and methods of feeding of the slug. 2. Its distribution. 3. The economic importance of slugs. 4. The shell of the slug. 5. Allies of the slug: Helix, Pupa, Limn sea, Physa, Planor- bis, Littorina, Fulgur, Fissurella, ^Eolis, Chiton, the Nautilus, and other cephalopods recent and fossil.
356 ZOOLOGY
XII. FRESH-WATER CLAM (Anodonta or Unio}
Venus may be substituted for these ; and Mya is a favorable object for this study. Anodonta or Unio may be obtained from most streams and ponds at any time of the year except midwinter. This exercise will therefore be best taken in the spring or autumn. To prepare animals for the study of the soft parts, place them in hot water (60° C.) for a few minutes; the valves will then open so that the muscles can be cut where they join the shell.
DRAWINGS
1. Exterior of left valve, showing lines of growth, beak, and margin. Natural size.
2. Interior of right valve ; name some of the more important parts, such as margin, scar of mantle, scars of adductor muscles, and retrac- tor of foot, hinge. Natural size.
3. Bit of fractured edge of burnt shell, to show layers, x 5.
4. Remove the left valve from the killed animal and draw the exter- nal form of the soft parts from the left side, x 2.
5. Laying back the mantle, draw in place gills (showing surface structure), body, foot, and labial palps; mark anterior, posterior, dorsal, and ventral surfaces of the body, x 2.
6. Draw an imaginary cross-section made through the middle of the body.
QUESTIONS TO BE ANSWERED BY INFERENCE FROM STRUCTURE
1. How does the shell grow?
2. How does the animal close its shell ; how open it?
3. How does the animal gain its food ?
OBSERVATIONS ON THE LIVING ANIMAL
Every student should be provided with the following : (1) vial con- taining finely powdered carmine in water; (2) vial of carmine in 5% acetic acid; (3) carmine in 5% sulphuric acid ; (4) carmine in sugar solution ; (5) pipette ; (6) 4-inch battery jar half full of water.
1. Notice in a living individual in the aquarium the movements of the mantle, especially at the posterior end.
LABORATORY WORK, XIII 357
2. Hold the clam just below the surface of the water and by means of a pipette place some carmine suspended in water near the poste- rior end. Notice the results. How are they to be interpreted ?
3. Offer carmine in sugar solution; in acetic acid; in sulphuric acid. Is there any difference in the results ?
TOPICS FOR FURTHER STUDY
1. Habitat and food of Anodonta (or Unio). 2. Geographical dis- tribution of fresh-water clams. 3. General development. 4. Allied animals from fresh water, such as the Unionidae and Cycladidae ; and from the sea, such as the Myidae, Veneridae, Arcidae, Aviculidae, Pecti- nidae, and Ostreidae.
XIII. STARFISH (Asterias vulgaris)
Starfishes can be readily got at low tide in rock pools and on piles and walls at the sea-shore. They may be transported alive consider- able distances, if packed in wet eel-grass or seaweed. The living animals may be placed for study in a soup-plate full of sea-water, or water containing about 2.5% sea salt. Dry preparations, for the study of the hard parts, may be made as follows : Leave a living starfish in a shallow dish of warm, fresh water until fully expanded. Next dip it into boiling water until hardened, and then dry it in the sun or in
a slow oven.
DRAWINGS
(Nos. 1, 2, 4, and 5 from dried specimen, No. 3 from an alcoholic one.)
1. Aboral view. Natural size.
2. Oral surface of arm showing ambulacral groove. Natural size.
3. Cross-section of arm with ambulacral feet, x 4.
4. Ambulacral ossicles, dissected out. x 2.
5. Spines from aboral surface, x 10.
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with a soup-plate full of salt water.
1. Observe the eyes, the ambulacral feet and their sucking disks, the gills upon the back. Has the starfish strict radial symmetry?
2. Note the method of locomotion by ambulacral feet. With the aid of a diagram show what takes place in a single foot.
358 ZOOLOGY
3. Invert the starfish ; observe and record the changes undergone in reassuming the normal position.
TOPICS FOR FURTHER STUDY
1. Habitat of starfish. 2. Food and economic importance. 3. Gen- eral history of development. 4. Allied forms ; Solaster and other starfishes, brittle stars, sea-urchins, holothurians, crinoids.
XIV. HYDRA
This exercise requires the use of a lens.
To obtain Hydra it will be necessary to search carefully in fresh- water pools. Lemna together with sticks and grass should be collected from the pools and put into an aquarium. The Hydras, which are attached to these objects, will then usually migrate in the course of a few days to the light side of the vessel, where they can be easily found. Hydras can be kept readily throughout the entire winter in a large glass jar containing Lemna and other plants, and Entomostraca for food. All the following exercises can be done on the living animal, and either the brown species (//. fusca) or the green species (H. viridis) may be employed.
DRAWINGS
(From living individuals')
1. Side view of a single Hydra, not budding, x 10.
2. Side view of a Hydra with buds, x 10.
(Optional, requires compound microscope.) Draw one of the ten- tacles of Hydra, showing discharged and undischarged nettling capsules, x 300.
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with the following: (1) 4-inch battery jar ; (2) 2-inch Stender dish ; (3) vial containing 5 % sugar solution ; (4) vial containing 5 % acetic acid ; (5) a few Daphnias in a watch-glass ; (6) pipette ; (7) needle ; (8) watch-glass ; (0) paste- board box of a slightly larger size than the battery jar and with a vertical slit half an inch wide along one side.
Place a Hydra in a watch-glass full of water.
LABORATORY WORK, XV 359
1. Touch the tentacles of the Hydra with a needle. What move- ments?
2. Drop cautiously and at intervals of a few minutes upon the sur- face of the water over the tentacles of the Hydra a drop of water, of susrar solution, of acid. What differences in the movements?
O
3. Bring a Daphnia (previously stranded) on the end of a needle to the tentacles of the Hydra. Note the result. With another Hydra, use a bit of plant tissue.
4. (This and the following experiment must extend through several day*.} Place a Hydra in a watch-glass with a little water, and by means of the needle and a penknife cut it into two or three pieces. Let the pieces expand and draw them. By means of a clean pipette place the pieces in the small Stender dish, in clean water. Draw the pieces again after twenty-four hours, and after a longer period if necessary.
5. Place in a 4-inch battery jar full of water containing Lemna and Entomostraca two or three large, budding, green Hydras. Cover the jar with the box, placing the slit next to the window. Note at short intervals for two weeks the position and number of Hydras in the jar.
TOPICS FOR FURTHER STUDY
1. The habitat and food of Hydra. 2. Other fresh-water or brack- ish-water hydroids (Cordylophora, Limnocodium) and the origin of fresh-water Hydrozoa. 3. Marine hydroids (Obelia, Sertularia, etc.) and their jellyfishes. 4. Sea-anemones and corals. 5. Corals as island builders. 6. Budding and the formation of colonies among animals. 7. Division of labor in colonies. 8. Regeneration in polyps.
XV. PARAMECIUM
This exercise requires the use of the compound microscope.
Twro or three weeks before Paramecia are needed, put hay and decaying leaves in stagnant water and keep in a warm room. When the water has become foul, Paramecia have probably appeared. To prevent the Paramecia on the slide from moving too rapidly, it is advisable to put them in a 2.5 % solution of gelatine in water. Study first with the low power, then with the high. To bring out the
360 ZOOLOGY
nuclei in the living animal, run a 5% or 10% aqueous solution of methyl green under the cover-glass by placing the solution at one edge of the cover-glass and drawing it under by filter paper placed at the opposite edge. To stain the plasma, a little iodine may be added ; this will kill, with explosion of trichocysts.
DRAWING (From observations on several individuals)
Whole animal, showing shape of body, cilia, vestibule, food- globules, non-contracting vacuoles, contracting vacuoles, nucleus, trichocysts. x about 200.
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with the following: (1) vial containing beef extract ; (2) vial containing finely powdered car- mine in water ; (3) common salt ; (4) pipette ; (5) filter paper.
1. Is the protoplasm in the body of Paramecium quiet or moving?
2. Place Paramecium in a drop of the gelatine solution. Cover with cover-glass. Run carmine-water under the cover-glass; select a quiet individual and observe how the carmine grains pass by it. Indicate by arrows placed outside the periphery of the drawing the direction of movement of the carmine. What do vou infer concern-
ti
ing the movement of the cilia? Do the grains whirl as much about a moving individual as about a quiet one? Can you explain? Why are not all the Paramecia carried off by the current when carmine is run under the cover-glass ?
3. Place upon a clean glass slide a drop of water containing Para- mecia. When they are uniformly distributed, put a few grains of common salt in the centre of the drop. After a few seconds observe and draw the distribution of the organisms. How is the result to be interpreted?
4. Place upon the glass slide a drop of water containing Paramecia; by means of a pipette (drawn to a fine point), add a drop of \ % to Tao % acetic acid ; after two or three minutes draw the distribution of the Paramecia. How do reactions to acids and to salts compare ? l
!See H. S. Jennings, American Journal of Physiology, May, 1899, and American Naturalist, May, 1899.
LABORATOEY WORK, XVI 361
5. Under a moderate power observe the reactions of Paramecium when it comes to the salt or acid.
TOPICS FOR FURTHER STUDY
1. Plow the Infusoria get into the aquarium. 2. The habitat and food of Paramecium. 3. Allies of Paramecium : Stentor, Vorti- cella, Carchesium, Euglena, the Suctoria, Amoeba, the Gregarinidse. 4. Economic importance of Amoeba and the Gregarinidse. 5. Repro- duction of Paramecium.
XVI. SMELT (Osmerus mordax)
Various other bony fishes may replace the smelt, e.g. brook trout (Salmo fontinalis), lake herring or white fish (Coregonus), perch (Perca).
DRAWINGS
1. Whole animal, from left side, fins extended, showing number of fin rays, position of lateral line, mouth, tongue, teeth, nostrils, anus, urinary openings, x 1 to "2.
2. Side view of a few trunk segments as seen after removal of skin.
3. Ventral view of head, gill cover removed, mouth open, probes passing from mouth through each of the gill slits. Show teeth and slime-glands, x 2 to 3.
4. Dorsal view of head, showing, when possible, form of brain seen through brain case, x 2.
5. Cross-section (5 mm. thick) of whole animal in front of anus and behind dorsal fin. Name organs as instructed by teacher.
6. Lateral view of vertebra, from the section mentioned in 4, isolated by boiling.
QUESTIONS ON EXTERNAL ANATOMY
1. How many rows of scales are there above the lateral line ; how many below ?
2. How many segments behind the head? Is this number constant? (Compare with two other individuals.)
3G2 ZOOLOGY
3. What special fitness in the form of the body to the habits of the fish?
OBSERVATIONS AND EXPERIMENTS ON THE LIVING ANIMAL
1. Role of fins in locomotion. By means of a cotton string wrapped around body, bind clown the pectoral fins and replace in water ; result? Bind ventrals similarly; result? Wrap string around tail and replace in water ; result? Conclusions?
2. How do the movements of the caudal fin cause the fish to progress?
TOPICS FOK FURTHER STUDY
1. Habitat and food of the species. 2. Distribution and economic importance. 3. Allied species : salmon, trout, white fish. 4. Other groups of fresh-water bony fishes: the darters, perch, sun fish, stickle- backs, silversides, minnows, pike, shad, suckers, catfish, eels. 5. Other kinds of fish : Amphioxus, lampreys, sturgeons, spoonbills, garpike, Amia. 6. The ontogeny of a bony fish. 7. The migrations of fish. 8. Artificial breeding and fish-hatching stations.
XVII. NEWT (Diemyctylus viridescens)
For this species may be substituted the small spring or brook salamanders (Desmognathns and Spelerpes), Amblystoma, or even Necturus. The small size of the brook salamanders makes them especially useful for external study and preservation in alcohol.
DRAWINGS (of convenient size}
1. Entire animal.
2. View of the left side of head, mouth open.
3. Left fore foot, dorsal surface.
4. Left hind foot, palmar surface.
5. Form of front lateral teeth, x 10.
QUESTIONS ON EXTERNAL ANATOMY
1. Which is the thumb side of hind foot?
2. Are the spots on the body arranged, according to any law ?
3. Are there two movable eyelids?
4. Where is the ear ?
LABORATORY WORK, XV III 363
OBSERVATIONS ON THE LIVING ANIMAL
1. How are the movements of appendages and tail correlated in lo- comotion («) on land, (6) in water ? Diagrams.
"2. Observe the instincts of the animal when placed in a box of earth Q damp and J dry) lighted on one side from the window and strewn with leaves and stones.
TOPICS FOR FURTHER STUDY
1. Habitat and food of the species studied. 2. Distribution of Amphibia. 3. Allied organisms in the United States: Desmogna- thus, Plethodon, Amblystoma, Amphinma, Nee turns, Siren ; their distribution and habitats. 4. Experiments upon changing Axolotl into Amblystoma. 5. Egg-laying of Urodela and general form- changes accompanying development.
XVIII. LIZARD (Anolis carolinensis)
This may be replaced by any other species. Where live lizards cannot be easily obtained, substitute a snake or tortoise and make appropriate changes in the following outline.
DRAWINGS
1. Entire animal, dorsal view, x 1 to 3.
2. Dorsal view of head, showing scales, especially the parietal scale, x 3.
3. Left side of head ; mouth open, tongue exposed, x 3.
4. Left fore foot, dorsal aspect, x 3.
5. Left hind foot, palmar aspect, x 3.
6. Outline of front lateral teeth, x 10.
7. Outline of scales on ventral side at base of tail. X 10.
8. Outline of scales on back, x 10.
QUESTIONS ON EXTERNAL ANATOMY
1. Which is the thumb side of the fore foot ? Why? Of the hind foot? Why?
2. What is the function of the structures on the pads of the toes ?
364 ZOOLOGY
3. Where is the ear-drum?
4. (This may best be studied on the living animal.') Is there a nicti- tating membrane, as in birds?
OBSERVATIONS ON THE LIVING ANIMAL
Each student should be provided with a set of Bradley's color cards.
1. Which eyelid is more used in winking, the upper or the lower ?
2. Locomotion : Order of movement of legs ; correlation of leg and tail movement.
3. Change of color : Effect of colored backgrounds (Bradley's colors1), of warming by holding in the hand, of stroking the back.
TOPICS FOR FURTHER STUDY
1. Habitat, food, and distribution of Anolis. 2. Common lizards of the region, if any. 3. Other interesting lizards, such as the chameleon, the blind worm (Anguis), the Gila monster (Heloderma), lizards of Europe (Lacerta), fossil Reptilia.
XIX. "ENGLISH" SPARROW (Passer domesticus)
This introduced bird can be obtained in most large cities in sufficient numbers. Recently killed birds are the most favorable for laboratory work. Subjection to fumes of carbon disulphide is a useful precau- tion against bird lice.
DRAWINGS
1. Side view (left). Name parts. Natural size.
2. Head and bill, side view, mouth open, showing tongue, x 2.
3. Foot (left), dorsal surface, x 2.
4. Foot (left), palmar surface, x 2.
5. Contour feather (from tail), x 2.
6. Plumage feather, x 3.
7. The egg. x 2.
QUESTIONS ON EXTERNAL ANATOMY
1. Color of: (a) eye ; (/>) bill; (c) feet ; (d) throat; (e) breast; (/) belly ; (//) crest ; (/*) side of head ; (/) back ; (/,-) wing ; (/) rump ; (m) tail feathers ?
1 Milton Bradley Company, Springfield, Mass.
LABORATORY WORK, XX 365
2. Number of tail feathers ?
3. Number of primaries ?
4. How many segments in the leg ; in the wing ?
TOPICS FOR FURTHER STUDY
1. The introduction of the ''English" sparrow into America and similar instances of introduction and spread of exotic species. 2. The food and habits of the " English "' sparrow in America. 3. The native sparrows. 4. Other groups of birds : thrushes, bluebirds, tit- mice, nuthatches, creepers, wrens, warblers, tan age rs, swallows, wax- wings, vireos, shrikes, larks, orioles, crows, flycatchers ; parrots and cockatoos; toucans and cuckoos, kingfishers; woodpeckers, humming- birds, swifts, goatsuckers ; pigeons ; grouse and fowl ; ostriches ; waders ; swimmers, and divers. 5. The migrations of birds ; migra- tion data. 6. Flight of birds. 7. The food and economic importance of birds. 8. The preservation of birds. 9. Fossil birds.
XX. MOUSE (Mm mustelus)
Tame mice may be obtained from bird fanciers in most of our large cities.1 They can be kept in the laboratory indefinitely. Galvanized wire cages with doors and galvanized iron bottoms are serviceable. Supply with cotton, hay, or excelsior for a nest. Keep at an equa- ble, moderate temperature, and pay great attention to cleanliness. Feed on oats and bread, with occasional fruit, carrot, and cooked meat.
DRAWINGS
1. Side view (left). Name parts. Natural size.
2. Head, dorsal view, x 1.5.
3. Fore foot (left), dorsal surface, x 2.
4. Fore foot (left), palmar surface, x 2.
5. Hind foot (left), dorsal surface, x 2.
6. Side view of skull, x 3.
7. Upper surface of lower jaw showing teeth, x 3.
8. Incisor tooth (free), x 10.
1 Mr. H. C. Ostendorf, 420 N. Eutaw St., Baltimore, has been found reliable by the writer, and keeps a stock on hand.
366 ZOOLOGY
OBSERVATIONS ON THE LIVING ANIMAL
Each student, or set of students, should be provided with the following: (1) a cage of wire netting about 8 inches cube, with a door on top ; (2) a tin box or small cigar box, closed except for a f-inch hole and small enough to be put into the cage.
1. Enumerate the kinds of activities of the mouse in the cage.
2. Bring a piece of toasted cheese to one side of cage. Note any change of movements.
3. Place the small box in the cage. Note the actions of the mouse. Does he go directly to the hole or does he find it by accident, or otherwise ?
TOPICS FOR FURTHER STUDY
1. The distribution of mice and rats. 2. The habits of rats and mice. 3. The food of mice. 4. The races of tame mice. 5. Other rodents. 6. Other mammals : the monotremes, marsupials, edentates, Cetacea, Ungulata, Insectivora. Carnivora, Cheiroptera, and Primates. 7. The descent of man.
XXI. DEVELOPMENT OF THE FROG'S EGG
The eggs of toads and even of Urodela may be substituted, although this outline accords closely with Anura only. Frog-spawn, may be obtained in April in ponds and marshes as jelly-like masses containing the eggs. Toad-spawn occurs as threads intertwining with the grass at the margins of shallow pools. Eggs may be obtained from animals in captivity by placing breeding males and females in a large glass aquarium in the laboratory. The eggs should be studied shortly after being laid and at various later periods.
DRAWINGS
(While it is desirable that these be ma fie from the living ef/r/s, they may be made from eggs killed in /tot water at 80° C.)
1. A bit of spawn with a few eggs in place, x 2.
2. Isolate eggs, watch and draw various stages till hatching. The series should include as many of the following stages as possible : cleavage, inorula, blastopore formation, medullary folds, gill covers,
METHODS OF EXAMINATION 367
gills, newly hatched tadpole, tadpole several days after hatching. (Optional, a series of tadpoles showing metamorphosis.) x 15 to 20. (Keep a record of the time — day, hour, minute — when each stage was drawn.)
EXPERIMENTS
1. Keep some of the same spawn in a refrigerator for ten days, then draw and compare with the eggs kept at normal temperatures for the same length of time.
2. At the time of formation of neural folds, free an embryo from the albumen, and add carmine grains to the (shallow) water. Note the direction of currents and motion of cilia.
3. Amputate the tail of a newly hatched larva and observe the result after a week or two.
4. Find the (approximate) specific gravity of a tadpole by placing one or two in each of the following solutions of gum arabic in water :
Per cent by weight, 33 16.5 11 8.2 3.3 1.65
Specific gravity, 1.11+ 1.06 1.037 1.028 1.011 1.006
The solution in which they tend, when motionless, neither to rise nor fall is of their specific gravity. Repeat with tadpoles just hatched and with those one week, two weeks, three weeks, and four weeks old.1
TOPICS FOR FURTHER STUDY
1. Effect of heat and light upon development. 2. Capacity of organisms for healing and regeneration. 3. Postembryonic develop- ment of the frog, Amblystoma, and Necturus. 4. General laws of development. 5. Development of the chick. (This should be illustrated by opening several eggs at various stages of development.)
It may interest teachers to have reproduced here the examination requirements of two universities which are exactly covered by the preceding outline : —
!See S. R. Williams iu the American Naturalist, February, 1900, p. 98.
368 ZOOLOGY
I. METHOD OF EXAMINATION IN ZOOLOGY FOR ADMISSION
TO THE LAWRENCE SCIENTIFIC SCHOOL, HARVARD UNIVERSITY.
The candidate is required to pass both a written and a laboratory examination. The written examination will test the range and thor- oughness of his knowledge of the subject. The laboratory examina- tion will test his skill in observation and experimentation, and his ability to apply names properly to the parts of the organisms studied.
At the time of the written examination the candidate must present the original note-book containing (with dates) the notes and drawings he has made in the course of his laboratory work, and bearing the endorsement of his teacher, certifying that the book is a true record of the pupil's own observations and experiments. An index of sub- jects should be appended.
II. METHOD OF EXAMINATION IN GENERAL BIOLOGY (ZOOLOGY
AND BOTANY) FOR ADMISSION TO THE JUNIOR COLLEGES, THE UNIVERSITY OF CHICAGO.
The candidate applying for admission credit in General Biology will be required : («) To submit to the examiner a note-book consist- ing of drawings and descriptions of the animals and plants studied. It is recommended that studies of at least fifteen principal forms be undertaken, that these studies be largely such as do not demand the use of a compound microscope, and that attention be given chiefly to those organisms that can be studied in a living condition; (!>} to de- monstrate, in the college laboratory, under the supervision of college officers, that he possesses some power to observe accurately and intelli- gently. More stress will be laid on correct observation and on the careful record thereof, than upon technical terms; (r) to answer in writing a few general questions about familiar animals and plants, such as the perch, crayfish, grasshopper, moss, fern, some common type of flowering plant, etc.
APPENDIX II
A LIST OF BOOKS DEALING CHIEFLY WITH ECOLOGICAL AND SYSTEMATIC ZOOLOGY OF AMERICAN ANIMALS.
A. GENERAL SYNOPTIC WORKS
Leunis, J. — Synopsis der Thierkunde. Dritte Auflage von H. Ludwig. 2 Bande. Hannover. 1883-86.
This is the nearest approach to a systematic manual, taking the place in Zoology which Gray's and Coulter's Manuals do in Botany. It deals chiefly with European species ; and has not been translated.
Thomson, J. A. — Outlines of Zoology. 3d edition, with 332 illustra- tions. New York : D. Appleton & Co. 1899. 819 pp.
An excellent condensed compendium ; in which, however, the struc- tural side predominates.
Riverside [formerly Standard] Natural History, edited by J. S. Kings- ley. 6 vols. large 8°. Boston and New York : Iloughton, Mifliin & Co. Price $30.
The most important large compendium written by American authors, somewhat after the plan of Brehm's Thierleben.
Cambridge Natural History, edited by S. F. Harmer and A. E. Shipley. New York : The Macmillan Company. 1894.
An English work of surpassing merit ; five volumes have ap'peared but the work is still far from complete.
Klassenund Ordnungen des Thierreich.es, edited (originally) by Bronn. Leipzig u. Heidelberg : C. F. Winter.
An extensive and thorough work. Although the whole work is not yet completed, some of the volumes are out of date. The most recent and important are the volumes on Protozoa, Porifera, Cu'lenterata, Vermes, Echiuodermata, Crustacea, Mollusca, Reptilia, and Birds. 2B 369
370 ZOOLOGY
Das Tierreich. Eine Zusammenstellung und Kennzeichnung der re- zenten Tierfornien. General redncteur : F. E. Schulze. Berlin : R. Friedlander und Sohu. 1890 —
A systematic account of every known species, with keys for their de- termination. An ambitions enterprise which will hardly be finished during one generation.
B. WORKS RELATING TO ANIMALS OF A PARTICULAR
HABITAT
Verrill, A. E. (and S. I. Smith).- -Report upon the Invertebrate Ani- mals of Vineyard Sound and the adjacent waters, in Report (of U. S. Fish Commission) on the Condition of the Sea Fisheries of the South Coast of New England in 1871 and 1872. (1873.) pp. 295-778.
An indispensable accompaniment of the zoologist at the sea-shore; separate copies can be purchased of dealers in scientific books.
Emerton, J. E. --Life on the Seashore. [For sale by BradJee Whid- den, Boston.]
C. GENERAL WORKS ON HABITS, ECOLOGY, AND
DISTRIBUTION
Verworn, M. — General Physiology. An outline of the science of Life.
Newr York : The Macmillan Company. 1899. G15 pp. Price
$4.00. Morgan, C. L. — Animal Life and Intelligence. New York: Edward
Arnold. 1891. 503 pp. Morgan, C. L. — Habit and Instinct. New York: Edward Arnold.
1896. 351 pp.
The two best books on the topics considered.
Lubbock, J. — On the Senses, Instinct, and Intelligence of Animals, with
special reference to Insects. International Sci. Ser., Vol. LXIV.
New York : D. Appleton & Co. 1888. Marey, E. J. — Movement. International Sci. Ser., LXXTII. New
York: D. Appleton & Co. 1895. Poulton, E. B. — The Colors of Animals. The International Scientific
Series, Vol. LXVII. New York: D, Appleton & Co. 1890.
BIBLIOGRAPHY: ANATOMY AND EMBRYOLOGY 371
Semper, K. - - Animal Life as affected by the Natural Conditions of existence. International Scientific Series, XXX. New York : D. Appleton & Co. 1881.
Even to-day the best book on Animal Ecology.
Wallace, A. R. - -Tropical Nature. London and New York: Macmil- lan & Co. 1895.
Wallace, A. R. — Geographical Distribution of Animals. 2 vols. Lon- don : Macmillan & Co. 1879.
Beddard, F. E. -- Text-book of Zoogeography. Cambridge (Eng.) Scientific Series. 1895.
D. WORKS DEALING CHIEFLY WITH ANATOMY AND
EMBRYOLOGY
Parker, T. J., and W. A. Haswell. - - Text-book of Zoology. 2 vols. Many illustrations. New York: The Macmillan Co. 1897.
Parker, T. J., and W. A. Haswell. --Manual of Zoology. Adapted for use of American Schools and Colleges. 563 pp. 327 figs. New York : The Macmillan Co. 1900.
Rolleston, G., and W. H. Jackson.- -Forms of Animal Life. 1888.
Lang, A.- -Text-book of Comparative Anatomy. Translated by Ber- nard. 2 vols. New York : The Macmillan Co. 1896.
Brooks, W. K. — Handbook of Invertebrate Zoology. For laboratories and seaside work. Boston : S. E. Cassino. 1882. [May be pur- chased of Bradlee Whidden, Boston.]
Korschelt, E., and K. Heider.- -Text-book of the Embryology of Inver- tebrates. 3 vols. New York : The Macmillan Co. 1899.
Balfour, F. M. - - A Treatise on Comparative Embryology. In 2 vols. London: Macmillan & Co. 1880-81.
Although decidedly out of date, yet gives the best general discussion of the subject.
Hertwig, 0. - Text-book of the Embryology of Man and Mammals.
Translated by E. L. Mark. New York : Macmillan & Co. 1892. Wilson, E. B. - - The Cell in Development and Inheritance. New York :
The Macmillan Co. 1896.
372 ZOOLOGY
E. PERIODICALS
Besides " Science" and " Nature," both published by The Macmillan Co., New York, there will be found of especial interest to the zoology student : —
The American Naturalist. A Monthly Journal devoted to the Natural Sciences in their widest sense. Published monthly by Ginn & Co., Boston. Price $4.00 per year.
This journal is publishing keys for the determination of North Amer- ican Invertebrates.
F. WORKS ON SPECIAL GROUPS INSECTS IN GENERAL
The Cambridge Natural History. Yols. V and VI. - - Peripatus, by A. Sedgwick : Myriapods, by F. G. Sinclair ; Insects, Parts I. and II., by David Sharp. Macmillan & Co., London and New York. 1895 and 1899.
Deals especially with Ecology.
Comstock, J. H. and A. B. — A Manual for the Study of Insects. Ithaca, N. Y. : Comstock Publishing Co. 1895. Price $3.75.
The best systematic treatise (with special reference to economic en- tomology) on Insects of the United States, with keys to families.
Comstock, J. H. --An Introduction to Entomology. Ithaca: Com- stock Publishing Co. 1888.
Unfinished, but more detailed than the Manual. Treats of Thysanura, Pseudoneuroptera, Orthoptera, Physopoda, Hemiptera, and Neuroptera only.
Comstock, J. H. — Insect Life. An Introduction to Nature Study and a guide for teachers, students, and others interested in out-of- door life. D. Appleton & Co. New York, 1897. 349 pp. Price $2.25.
Packard, A. S. --Entomology for Beginners. Henry Holt & Co., New York. 1888. Price $1.40.
Packard, A. S.--Half Hours with Insects. Boston: C. E. Lauriat. 1881.
BIBLIOGRAPHY, I 373
Smith, J. B. — Economic Entomology. Philadelphia: J. B. Lippin- cott & Co. 1896. Price $2.50.
Packard, A. S.-- Fifth Report of the United States Entomological Commission [U. S. Department of Agriculture], being a revised and enlarged edition of Bulletin No. 7 on Insects Injurious to Forest and Shade Trees. Washington : Gov't Printing Office. 1890. 928 pp. 306 text figures and 40 plates.
A valuable aud inexpensive treatise; can usually be obtained of deal- ers in second-hand books.
Miall, L. C. - - The Natural History of Aquatic Insects. London and New York: Macmillan & Co. 1895. Price $1.75.
•
Lubbock, John. — On the Origin and Metamorphoses of Insects. Na- ture Series. London and New York : Macmillan & Co. 1895.
McCook, H. C. — Tenants of an Old Farm. Leaves from the Note- book of a Naturalist. New York : Fords, Howard & Hulbert. 1885.
Riley, C. V. — An Enumeration of the published synopses, catalogues, and lists of North American Insects. U. S. Dept. of Agriculture, Division of Entomology, Bull. No. 19. 1888. 77 pp.
A very valuable bibliography.
Riley, C. V.-- Directions for Collecting and Preserving Insects. Smithsonian Institution, Washington, D. C., 1892. Price 25 cents.
I. ORTHOPTERA, NEUROPTERA, HEMIPTERA, ETC.
Scudder, S. H. — Guide to the Genera and Classification of the North
American Orthoptera found north of Mexico. Cambridge : E.
W. Wheeler. 1897. 89 pp. Scudder, S. H. -- Revision of the Orthopteran group Melanopli
(Acridiidse), with special reference to North American forms.
Proceedings U. S. National Museum, XX. pp. 1-421. Plates
1-26. 1897. Calvert, P. P. -- Catalogue of the Odonata (Dragon-flies) of the
vicinity of Philadelphia, with an introduction to the study of
this group of insects. Trans. American Entomological Society,
Philadelphia. Price $1.00.
374 ZOOLOGY
Hagen, H. — Synopsis of the Neuroptera of North America, with a list of South American species. Smithsonian Miscellaneous Collections. Washington, D. C. 1861.
Banks, N.--A Synopsis, Catalogue, and Bibliography of the Neu- ropteroid Insects of Temperate North America. Trans. Ameri- can Entomological Society, Philadelphia. [Sec'y Amer. Entom. Soc. Price -11.00.]
Osborn, H. — Classification of Hemiptera. Entomologica Americana. Vol. I., pp. 21-27. 1885.
II. LEPIDOPTERA AND HYMENOPTERA
Scudder, S. H. — Brief Guide to the Commoner Butterflies of the Northern United States and Canada. Henry Holt & Co., New York. 1893. Price $1.25.
French, G. H.--Tlie Butterflies of the Eastern United States. For the use of classes in Zoology and private students. Philadelphia : Lippincott & Co. 1886.
Scudder, S. H. — The Butterflies of the Eastern United States and Canada, with special reference to New England. 3 vols. Cam- bridge, Mass. Published by the author. 1889.
Edwards, W. H. — The Butterflies of North America. Boston : Houghton, Mifflin & Co.
Holland, W. J. - -The Butterfly Book. A popular guide to a knowl- edge of the butterflies of North America, with 48 plates in color photography. New York : Doubleday & McC lure Co. 1898.
Knobel, E. — The Day Butterflies and Dusk Flies of New England ; how to find and know them (1895); also The Night Moths of New England; how to determine them readily (1895). Boston: Bradlee Whidden.
Cresson, E. T. — Synopsis of the Families and Genera of the Hytne- noptera, North of Mexico, together with a catalogue of the described species and bibliography. Trans. Amer. Entom. Soc., Suppl. vol., Pt. I., 1887. [Sec'y Amer. Entomological Society, Philadelphia. Price $3.00.]
Lubbock, J. --Ants, Bees, and Wasps. Internat. Sci. Series, Vol. XLII. New York ; P, Appleton & Co. 1882.
BIBLIOGRAPHY, VI 375
III. COLEOPTERA
LeConte, J. L., and G. H. Horn. -- Classification of the Coleoptera of North America. [Can be purchased of the Secretary of the American Entomological Society, Philadelphia. Price $2.50.]
Hoffmann, E. - -The Young Beetle Collector's Handbook. New York: The Macmillan Company. 1897. 178 pp., 20 color plates.
This book deals with European species; but many are closely related to ours.
Knobel, E. - - Beetles of New England and their kind. A guide to know them readily. Boston : Bradlee Whidden. 1895.
IV. DIPTERA
Williston, S. W. — Manual of North American Diptera. Second Edition, 1896. Jas. T. Hathaway, New Haven, Conn. Price $2.25.
Knobel, E. — The Mosquitoes, Gnats, Crane-flies, Midges, and Flies of the Northern States. Boston : Bradlee Whidden. 1897.
V. MYRIAPODA
Bollman, C. H. — The Myriapoda of North America. Bulletin U. S. National Museum, No. 46. 1893.
VI. ARACHNOIDEA
Emerton, J. H. — The Structure and Habits of Spiders. Salem,
Mass. 1878. Price $1.50. Emerton, J. H. — New England Spiders [of various Families]. In
Transactions Connecticut Academy, New Haven. Peckham, G. W. and E. G. — North American Spiders of the Family
Attid?e. Transactions Wisconsin Academy of Science, Arts,
and Letters, Madison, Wis. Vol. V1T., 1888. 256 pp., 2 plates. Peckham, G. W. and E. G. --Some Observations on the Mental
Powers of Spiders. Journal of Morphology, Vol. L, Dec., 1887. McCook, H. C.-- American Spiders and their Spinning Work: a
Natural History of the Orb-weaving Spiders of the United States,
with Special Regard to their Industry and Habits, 3 vols. 4°,
376 ZOOLOGY
1889-93; 372+479 + 406 pp.; 353 + 401 wood cuts; 35 plates. Philadelphia : published by the author [Academy Nat. Science, Philadelphia].
Very valuable and readable treatise.
McCook, H. C. — The Natural History of the Agricultural Ant of
Texas. Philadelphia, 1879. Kraepelin, K. --Scorpiones and Pedipalpi. Das Tierreich, 8. Lie-
ferung. Berlin : K. Friedlander und Solm. 1899. Weed, C. M. --A Descriptive Catalogue of the Harvest Spiders
(Phalangiida?) of Ohio. Proc. U. S. National Museum, Vol.
XVI., pp. 543-563, 3 plates. 1893.
CRUSTACEA
Stebbing, T. R. R.--A History of Crustacea, Recent Malacostraca.
International Scientific Series, Vol. 71. New York : D. Appleton
&Co. 1893. Rathbun, R. - - Natural History of Economic Crustaceans. In Bulletin
U. S. Fish Commission for 1889, pp. 763-830, plates 260-275 and
plate cxxi. 1893.
VII. MALACOSTRACA
Huxley, T. H. — The Crayfish. An Introduction to the Study of
Zoology. International Scientific Series, Vol. XXVIII. 1880. Faxon, M. - - A Revision of the Astacidae. Part I. : The Genera
Cambarus and Astacus. Mem. Mus. Comp. Zool., Vol. X. No. 4.
Cambridge, Mass. 1885. Ill pp., 11 plates. Herrick, F. H. - - The American Lobster : A Study of its Habits and
Development. Bulletin U. S. Fish Commission, Vol. XV., for
1895. 252 pp., 54 plates. 1896. Kingsley, J. S.-- Synopses of North American Invertebrates: III.
The Caridea of North America ; IV. Astacoid and Thalassinoid
Crustacea. American Naturalist, Vol. XXXIII. Sept. and Oct.,
1899. Benedict, J. E., and Mary J. Rathbun. - • The Genus Panopeus.
Proceedings U. S. National Museum, Vol. XIV., pp. 355-385, 5
plates. 1891.
BIBLIOGRAPHY, X 377
Rathbun, Mary J. --Catalogue of the Crabs of the Family Periceridse
[Spider Crabs] in the U. S. National Museum. Proceedings U. S.
National Museum, Vol. XV., pp. 231-277; 3 plates. 1892. Rathbun, Mary J. — Synopses, etc. VII. The Cyclometopous or
Cancroid Crabs of North America. American Naturalist, Vol.
XXXIV. Feb. 1900.
VIII. ENTOMOSTRACA
Herrick,C. L.,and C.H. Turner. — Synopsis of the Entomostraca of Min- nesota : Copepoda, Cladocera, and Ostracoda. Geological and Natural History Survey of Minnesota. 1895.
Giesbrecht, W., and 0. Schmeil. Copepoda: I. Gymnoplea. Das Tier- reich, 6. Lieferung. Berlin : R. Friedliinder und Sohn. 1898. Includes the free-swimming marine species.
WORMS
Cambridge Natural History. Vol. II. [Flatworms, Mesozoa, Werner- tin i ; threadworms, Sagitta, rotifers, polychset worms, earth- worms, leeches, Gephyrea, Phoronis, Bryozoa.] New York: The Macmillan Company. 1896.
IX. OLIGOCH/ETA AND LEECHES, GEPHYREA AND
BRYOZOA
Darwin, Charles.- -The Formation of Vegetable Mould through the action of Worms, with observations on their Habits. New York : D. Appleton & Co.
Michaelsen, W. — Oligochseta. Das Tierreich, 10. Lieferung. Berlin: R. Friedliinder und Sohn. 1900.
Davenport, C. B. — Synopses, etc. I. Fresh-water Bryozoa. Ameri- can Naturalist, Vol. XXXIII, July, 1899.
X. POLYCH^ETA AND LOWER WORMS
Verrill, A. E. - - New England Annelida. Part I., with Plates III.-XII. Trans. Connecticut Academy, Vol. IV., Pt. 2. 1881.
378 ZOOLOGY
Andrews, E. A. — Report upon the Annelida Polychreta of Beaufort, North Carolina. Proc. U. S. National Museum, Vol. XIV., pp. 277-302, 7 plates. 1891.
Johnson, H. P. — A preliminary Account of the Marine Annelids of the Pacific Coast, with Descriptions of New Species. Proc. Cali- fornia Acad. of Sciences, Vol. I., No. 5. 1897.
Montgomery, T. H. — Synopses, etc. II.: Gordiacea (Hair-worms). American Naturalist, Vol. XXXIII. Aug., 1899.
Ward, H. B. - - The Parasitic Worms of Man and the Domestic Ani- mals, in Report for 1894 of Nebraska State Board of Agriculture. Lincoln, Neb. 1895.
XL AND XII. MOLLUSCA
The Cambridge Natural History : Vol. III. : Mollusca, by A. H. Cooke. New York: The Macmillan Company. 1896.
Tryon, G. W., Jr. -- Structural and Systematic Conchology : an intro- duction to the Study of the Mollusca. 3 vols. 140 plates. Philadel- phia : published by the author. [Price, $ 6.00 ; for sale by S. R. Roberts, Glen Ridge, N. J.]
Gould, A. A. - - Report on the Invertebrata of Massachusetts. 2d edi- tion, by Binney. 1870. 52+ pp. 528 figures. Devoted to Mollnsca and Tunicata.
Apgar, A. C. — Molluscs of the Atlantic Coast of the United States, south to Cape Hatteras. [Copies bound in cloth, for sale by author, Trenton, N. J. Price, $1.00.] A very convenient book for the pocket.
Ingersoll, Ernest, and J. A. Ryder. — Natural History of Economic Molluscs of the United States. Bulletin U. S. Fish Commission for 1889. pp. 687-758. plates 253-259. 1893.
RADIATES
Agassiz, Elizabeth C., and A. Agassiz.-- Seaside Studies in Natural History. Marine Animals of Massachusetts Bay. Radiates. Boston : Ticknor & Fields. 1865.
Fewkes, J. W. — An Aid to a Collector of the Coelenterata and Echinodermata of New England, with cuts. Bull. Essex Insti- tute, Vol. XXII I., pp. 1-2. [Sec'y Essex Institute, Salem.]
BIBLIOGRAPHY, XIV 379
XIII. ECHINODERMATA
Agassiz, A. — North American Starfishes. Memoirs Museum Com- parative Zoology at Harvard College, Vol. V., No. 1. 1877. 137 pp. and 20 plates.
Agassiz, A. - - Revision of the Echini. Illustrated Catalogue of the Museum of Comparative Zoology at Harvard College, No. VII., 2 Parts. 1872-1873.
Lampert, K. - - Die Seewalzen (Holothuroiclea). Eine Systematische Monographic mit Bestimmungs- und Verbreitungs- Tabellen. Weisbaden : C. W. Kreidel. 1885. 4°. 310 pp., 1 plate.
Brooks, W. K. — Handbook of Invertebrate Zoology. Boston : Cassino. 1882.
Has au excellent chapter on the development of Echinoderms.
XIV. CCELEXTERATES
Trembley, A. — Memoires pour servir a 1'histoire d'un genre de Po- lypes d'eau douce a bras en forme de cornes. Leyden. 174-4. 4°. 323 pp., 13 plates.
A remarkable memoir on Hydra ; obtainable from European dealers in second-hand books.
Agassiz, L. - - Contributions to the Natural History of the United
States of North America. Vols. III. and IV. Second Monograph,
in five parts. - - 1. Acalephs in general. — II. Ctenophorae. — III.
Discophome. - - IV. Hydroidje. - - V. Homologies of the Radiata.
With 46 plates. Boston : Little, Brown & Co. 1860, 1862. Hincks, T.--A History of the British Hydroid Zoophytes. 2 vols.
London : Van Voorst. 1868. Vol. I. text, — Vol. II. plates. Price
42s. Allman, G. J. - - A Monograph of the Gymnoblastic or Tubularian
Hydroids. London : Ray Society. 1871. 4°. pp. 450, 23 plates. Darwin, Charles. - The Structure and Distribution of Coral Reefs.
New York : D. Apple ton & Co. [First published, London,
1842.] Agassiz, A.-- A Visit to the Great Barrier Reef of Australia in the
Steamer " Croydon," during April and May, 180G. Bull. Museum
380 ZOOLOGY
of Comparative Zoology at Harvard College, Vol. XXVIII.
April, 1898. Bowerbank, J. S. — A Monograph of the British Spongiadae. 4 vols.,
numerous plates. London : Ray Society. 1861-1882. Hyatt, A. - - Guides for Science Teaching. III. Commercial and Other
Sponges. Boston : Heath & Co. 1893. Potts, Edward. — Contributions toward a Synopsis of the American
forms of Fresh-water Sponges, with descriptions of those named
by other Authors and from all parts of the World, with 8 plates.
Proc. Acad. Nat. Science, Philadelphia, 1887, pp. 158-279.
XV. PROTOZOA
Biitschli, 0. -- Protozoa, Bronn's Klassen mid Ordnungen des Thier- reiches. Leipzig u. Heidelberg : C. F. Winter. 1889.
Kent, W. Saville. - - A Manual of the Infusoria : including a descrip- tion of all known flagellate, ciliate, and tentaculiferous Protozoa, British and foreign, and an account of the Organization and Affinities of the Sponges. 2 vols. and vol. of plates. London : D. Bogue. 1880-1882.
Leidy, J. — Fresh-water Rhizopods of North America. Washington : Government Printing Office. 1879.
VERTEBRATES IN GENERAL
Jordan, D. S. — Manual of the Vertebrates of the Northern United States. 5th Edition. Chicago : McClurg.
Systematic, with keys.
Kingsley, J. S. -- Text-book of Vertebrate Zoology. New York: Holt & Co. 1899.
About equally devoted to Morphology and Classification.
Darwin, C. — The Variation of Animals and Plants under Domestica- tion. 2 vols., 2d edition. New York : D. Appleton & Co. 1894. Domestic races of various vertebrates.
NOTE. — lu many States, the Geological Surveyor Natural History Survey Reports contain lists of vertebrates found in the State.
BIBLIOGRAPHY, XVIII 381
XVI. PISCES
Goode, G. B. — American Fishes. A popular treatise upon the Game and Food Fishes of North America, with especial reference to habits and methods of capture. New York : Standard Book Co. 1888.
Jordan, D. S., and B. W. Evermann.- - The Fishes of North and Middle America. Bulletin U. S. National Museum, No. 47. 4 parts. Washington : Gov't Printing Office. 1898. 313(3 pages and atlas.
An exceedingly valuable work, full of biological data ; with keys to genera and species. Atlas not yet (1899) published.
XVII. AMPHIBIA
Gage, S. H. — Life History of the Vermilion-Spotted Newt (Die-
myctylus viridescens Rat'.). American Naturalist, Dec., 1891. Ritter, W. E. - - Diemyctylus torosus Esch. The Life History and
Habits of the Pacific Coast Newt. Proc. California Acad. of
Sciences. 3d series. Zoology. Vol.1., pp. 73-114. 1897. Wilder, H. H. - - Desmognathus fusca (Rafinesque) and Spelerpes bili-
neatus (Green). American Naturalist, Vol. XXXIII., pp. 231-246.
March, 1899. Kirkland, A. H. - - The Habits, Food, and Economic Value of the
American Toad. Hatch Experiment Station, Amherst, Mass.,
Bull. No. 46. 1897. Mivart, St. George. - - The Common Frog. Nature Series. London :
Macmillan & Co. 1881. Boulenger, G. A. — The Tailless Batrachians of Europe. London : Ray
Society. 1897-1898. Jordan, E. 0. The Habits and Development of the Newt. Jour, of
Morphology, Vol. VIII., No. 2. 1893. Sherwood, W. L. — The Frogs and Toads found in the Vicinity of
New York. Proceed. Linn. Soc. of New York, No. 10. 1898.
XVIII. REPTILIA
Agassiz, L. — Contributions to the Natural History of the United States of America. First Monograph. II. North America Testudi-
382 ZOOLOGY
nata ; III. Embryology of the Turtle. Vol. 2. Boston : Little, Brown & Co. 1857.
To be obtained from dealers in second-hand books.
Taylor, W. E.- -The Box-Tortoises of Xorth America. Proc. U. S. National Museum, Vol. XVII., pp. 573-588. 1895.
XIX. BIRDS
Newton, Alfred, and Hans Gadow. — A Dictionary of Birds. London : Adam eSt Charles Black. 1893-1896.
Coues, Elliott. - - Key to Xorth American Birds. Boston : Estes & Lauriat. 1896. 906 pp.
Ridgeway, R. — A Manual of Xorth American Birds. 2d Ed. Phila- delphia: J. B. Lippincott Co. 1896.
Chapman, F. M. - - Bird Life. A Guide to the Study of our Common Birds. Xew York : D. Appleton & Co. 1897.
Parkhurst, H. E. --How to Xame the Birds. Xew York: Charles Scribner's Sons.
Wright, Mabel 0., and E. Coues. --Citizen Bird. With 111 illustra- tions by L. A. Fuertes. Xew York : The Macmillan Co. 1898.
Besides these are a score or more good books on American birds, and guides to their study. The foregoing are representative.
XX. MAMMALIA
Flower, W. H., and Lydekker, R.--An Introduction to the Study
of Mammals, living and extinct. London : Adam and Charles
Black. 1891. Lydekker, R. - - A Geographical History of Mammals. Cambridge
Geographical Series. Cambridge (Eng.), at the University Press.
1886. [The Macmillan Co., Xew York. Price lO.s. 6^/.] Mivart, St. George. --The Cat. An Introduction to the Study of
Backboned Animals. Xew York : Scribner's. 1881.
XXI. DEVELOPMENT OF THE FROG
Morgan, T. H. - The Development of the Frog's Egg : An Intro- duction to Experimental Embryology. Xew York : The Mac- millan Co. 1897.
APPENDIX III
SYNOPSIS OF THE ANIMAL KINGDOM
GROUPS OF ANIMALS ARRANGED APPROXIMATELY IN AN ASCENDING SERIES; WITH REFERENCES TO EVERY FAMILY MENTIONED IN THE MAIN TEXT; AND WITH DEFINITIONS OF THE CLASSES AND ORDERS
E. — Owing to the method employed in the text of proceeding from a type to the allied groups, the systematic relations of the organisms considered are often obscured. This synopsis is intended to make these, relations clearer. It can also be used as a systematic index of the book. Moreover, the student con use it in reviewing his knowledge of the text, and as a key for the deter- mination of the class in wlijdi a specimen falls. The teacher can employ it as a guide to collecting illustrative material; for every family mentioned should, as far as possible, be illustrated by specimens or good .figures.
In the synopsis group-names printed in full-face are phyla ; in LARGE CAPITALS, classes; in SMALL CAPITALS, orders; in italics, families. Subphyla, subclasses, and suborders are indicated by bracketing. Thus [CILTATA] is a subclass. Numbers in parentheses refer to pages of the text.
PROTOZOA
Animals composed of a single cell ; or, if of several cells, these are of one kind.
RHIZOPODA. Protozoa with retractile psendopodia: Amoeba(227).
SPOROZOA. Protozoa without appendages; internal parasites (227).
FLAGELLATA. Protozoa without cilia but with one or more flagella (225).
383
384 ZOOLOGY
INFUSORIA. Protozoa with cilia or sucking tentacles (222).
[CILIATA]. Locomotor, with cilia: HOLOTRICHA (Parame- cium, 224); HETEROTRICIIA (224) ; PERITRICHA : Vorticella (225). [SUCTORIA]. Sessile, with sucking tentacles (225).
OELENTERATA
Animals of radial structure, whose digestive cavity is lined by the body-wall (205).
[SPONGIARIA]
Ccelenterata whose body-wall is perforated by incurrent pores (205).
[CNIDARIA]
Coelenterata whose body-wall is not perforated by incurrent pores, and which have nettling organs of some sort (205).
HYDROZOA. Cnidaria whose body is composed of more than two rays and contains a simple cavity. HYDROMEDUS.E, attached Hydro- zoa in hydroid stage ; medusa simple : Hydroidce (208) ; Hydrocoral- lidce (208); Tubularidce (208) ; Campanularidce (209); Traclwmedusce, (Zygodactyla, 212). SIPHONOPHORA, a free swimming colony of Hydrozoa (212).
SCYPHOZOA. Cnidaria with many radii, and with radial parti- tions in cavity of body (214).
CTENOPHORA. Cnidaria with only two radii, and rows of cilia- plates (219).
SCOLECIDA
Animals of worm-like form, with bilateral, unsegmented body.
PLATYHELMINTHES. Bilaterally symmetrical, soft-bodied animals, without true segmentation of the body ; flattened in a dorso- ventral direction, and having body-cavity filled with a loose meshwork of cells. TURBELLARIA, free-living flatworms whose body is cov- ered by cilia ; alimentary tract with only one opening to the exte- rior: Planaria (153). TREMATODA, parasitic, without cilia in the adult; the mouth leads into a forked food-canal without anus: Dis- tomum (153). CESTODA, elongated tape-like intestinal parasites, without mouth or food-canal : Tsenia (156). NEMERTIXI, body more or less flattened ; food-canal with mouth and anus ; a separate pro- trusible proboscis (158).
SYNOPSIS OF THE ANIMAL KINGDOM 385
NEMATHELMINTHES. Bilateral, unsegmented, round-worms; usually with alimentary tract, mouth, and anus: Ascaris (151).
ROTIFER A. Small aquatic Scolecida, with ciliated band around mouth, and a special organ for attachment, the foot; wheel-animal- cules.
BRYOZOA. Scolecida in which the ciliated band is carried out 011 a series of tentacles surrounding the mouth ; form colonies by bud- ding. ENDOPROCTA, Bryozoa with head and stalk, and crown of tenta- cles surrounding both mouth and anus (1-43). ECTOPROCTA, with anus outside tentacular corona (143).
MOLLUSCA i
Animals with unsegmented body and without jointed appendages. Usually with a shell and with a muscular organ of locomotion, the foot.
LAMELLIBRANCHIATA. Mollusca with nearly symmetrical body, leaf-like gills, and a shell composed of two valves. Ledidce (187); Arcidce (184); Mytilidce (184); Aviculidce (185); Pectinidce (186) ; Ostreidce (187) ; Unionidce (179) ; Cycladidce (180) ; Mactridce (182); Veneridce (183); Myidce (182); Solenidce (182); Pholadidce (181); Teredidce (181).
GASTROPODA. Mollusca with head, feelers, and eyes, an un- paired foot, and a shell that is univalve when present. AMPHINEURA, with strict bilateral symmetry, no externally visible gills, and usu- ally a shell composed of eight pieces: Chiton (171). PROSOBRANCHI- ATA, with gills in front, shelled and operculate : Acmceidce (170) ; Patellidce (170); Fissurellidce (170); Natiddce (168); Calyptraidce (Crepidula, 169) ; Littorinidce (167) ; Muricidce (Urosalpinx, 169) ; Fasciolariidce (Fulgur, 168) . OPISTHOBRANCHIATA, with gills behind heart; if shelled, without operculum ; JEolidiidce (171). PULMONATA, breathing by means of lungs, no operculum : Auriculidce (165) ; Lim- nceidce (166) ; Limacidce (161) ; Helicidce (164) ; Pupidce (165).
CEPHALOPODA. Mollusca with large head, mouth surrounded by a circle of arms, and funnel-shaped foot. Argonautidce (172); Spirulidce (172) ; Loliginidce (172) ; Nautilidce (173).
1 This classification, unlike that of the text, follows Cooke in his " Mol- lusca."
2c
386 ZOOLOGY
ECHINODERMATA
Animals of a prevailingly radial structure, with intestinal wall dis- tinct from body- wall and with calcareous plates in the skin (192).
CKINOIDEA. Sessile Echinodermata, having a cup-shaped body (203).
ASTEROIDS A. Star-shaped Echinodermata, with a furrow along the under side of the arms (193).
OPHIUROIDEA. Star-shaped Echinodermata, with ungrooved arms (198).
ECHINOIDEA. With armless, globular, or cake-shaped body (199).
HOLOTHUROIDEA. Worm-like, with tentacles around' mouth (201).
ANNELIDA
Bilateral, segmented worms without jointed legs.
POLYCtLETA. Annelida possessing parapodia on one or more segments, and with many bristles on parapodia. ERRANTIA, free- swimming Polychaeta: Autolytus (147), Lepidonotus (147), Xe- reis (145), Euglycera (147). SEDKNTARIA, Polychaeta which live in tubes composed of mud, sand, or lime: Cirratulus (149), Amphi- trite (150), Polycirrus (150), Cistenides (151), Clymenella (150), Serpula (151).
OLIGOCHJETA. Annelida without parapodia and with few setae ; living in fresh water or in the ground. LIMICOL^E, aquatic : Xais (137); Dero (137); Tub if ex (136). TERRICOL.*:, earth-inhabiting: Allolobophora, Lumbricus (133).
GEPHYREA. Annelida having sessile habits and consequently without external segmentation in the adult, setae sometimes present. Phascolosoma (139), Echiurus (139).
HIRUDINEA. Annelida with short rings or none at all and with a ventral sucker ; "bloodsuckers." Clepsine (141) ; Nephelis (140).
ARTHROPODA
Symmetrical, segmented animals, with jointed appendages. CRUSTACEA. Typically, aquatic and gill-bearing Arthropoda. Two pairs of antennae, except in Gigantostraca.
SYNOPSIS OF THE ANIMAL KINGDOM 887
[ENTOMOSTRACA]. Crustacea with varied number of pairs of appendages ; usually of small size. BRANCHIOPODA, mandibles without palps, numerous legs (127). TRILOBITA, fossil (130). CLA- DOCKRA, mandibles palpless, few legs (126). OSTRACODA, palp on mandible, only two pairs of legs (127). COPEPODA, elongated Crusta- cea, with only one pair of maxillae ; females with external ovisacs (127). CIRRIPEDIA, attached Crustacea (barnacles, 129).
[MALACOSTRACA]. Crustacea with nineteen pairs of appen- dages. AMPHIPODA (112). ISOPODA (112). CUMACEA (112). STO- MATOPODA (111). PODOPTHALMATA : [MACRURA], large-tailed Podopthalmata : Candida (104); Astacidce (97); Thalassinidce (105) ; Paguridce (105) ; Hippidce (107). [BRACHYURA], crabs : Ozyrhyncha (107) ; Cyclometopa (108) ; Catometopa (HO).
[GIGANTOSTRACA]. Crustacea with five pairs of appen- dages on cephalo-thorax, abdomen without feet; body ends in a long telson, Limulus (11-4).
ARACHNOIDEA. Air-breathing Arthropoda without antennae. ACARINA, rnites (95). PYCNOGONIDA, sea-spiders (95). ARENEIXA, spiders: Saltigradcv (90); Citigradce (89); Later! ffradce (89); Tubi- telarice (88) ; Retitelarice (87) ; Orbitelariw (86) ; Terr it elci rice (85). PHALANGINA, harvest-men (93). ARTHROGASTRA, scorpions (92).
TRACHEATA. Air-breathing Arthropoda, with one pair of an ten use.
[MYRIAPODAJ. Tracheata with distinct head and abdomen, all the segments of the abdomen bearing appendages. CIIILOPODA, centipedes : Scutigeridce (75) ; Lithob.iidce (75) ; Scolopendridce (76) ; Geophilidce (76). DIPLOPODA, millipedes : Julidce (76) ; Polydesm!<l<c (77). SYMPHYLA : Scolopendrella (78), Pauroptis (77).
[HEXAPODA]. Tracheata with only three pairs of legs, con- fined to thorax. ORTHOPTERA, Hexapoda with two pairs of wings, masticating mouth-parts, incomplete metamorphosis: Forficulidce (9) ; Blattidce (8); Mantidce (8); Phasmidas (7); Acrid idee (2); Locust idee (5); GrilUdre (4). XEUROPTERA, Hexapoda with two pairs of net- veined wings ; biting mouth-parts, metamorphosis complete or in- complete: Odonata (9); Ephemeridce (10) ; Termitidce (11); Sird'uhe. Corydalis (12). HEMIPTERA, Hexapoda with two pairs of wings or none, sucking and piercing mouth-parts, incomplete metamorphosis. [HETEROPTERA], upper wings leathery: Reduviidce (12>. [HoMOp-
388 ZOOLOGY
TERA], wings alike: Cicada (14) ; [here, also, plant lice and animal lice]. DIPTERA : Hexapoda with (typically) one pair wings; pierc- ing" and sucking mouth-parts ; complete metamorphosis. [APHANIP- TERA], fleas (71). [PUPIPARA] : Hippoboscidce (71). [BRACHYCERA], true flies : Muscidce (62) ; CEstridce (65) ; SyrpJiidce (66) ; Asilidce (66) ; Tabanidce (66); Simuliidce (67). [XEMATOCERA], gnats: Ceci- domyidce (67) ; Culicidce (69) ; Tipulidce (70). COLEOPTERA, Hexa- poda whose fore wings are modified into wing covers ; hind wings folded when not in use : Coccinellidce (55) ; Chrysomelidce (54) ; Cerambycidce (54) ; Curculionidce (53) ; Scolytidce (53) ; Tenebrionidce (52) ; Lampyridce (51) ; Elateridce (51) ; Buprestidce (51) ; Lamelli- cornia (49) ; Lucanidce (49) ; Dermestidce (49) ; Silphidce (48) ; Staphy- iinidce (47) ; Hydrophilidce (47) ; Gyrinidce (46) ; Dytiscidce (46) ; Carabidce (45) ; Cicindelidie (45). LEPIDOPTERA, Hexapoda with two pairs of scale-covered wings, sucking mouth-parts, complete meta- morphosis : Tineidce (29) ; Tortricidce (29) ; Pyralidce (29); Geometridce (28); Noctuidce (19,28); Bombycidce (26); Arctiidce (24); Xylotropi- dce (23) ; Spliingidce (22); PapiUonidce (21). HYMENOPTERA, Hexa- poda with two pairs of membranous wings ; biting and licking mouth- parts ; complete metamorphosis: [PHYTOPHAGA], plant-eating (38). [ENTOMOPHAGA] insect parasites (38). [ACULEATA] stinging: For- micidce (34) ; Fossoria (34) ; Vespidce (33) ; Apidce (31).
CHORDATA
Animals which possess, at some time of life, throat slits and a dor- sal supporting rod or chorda.
[HEMICHORDA]
Animals of w7orm-like form, showing gill-slits like fishes. Balano- glossus (251).
[TUNICATA]
Chordata which are either attached or form colonies or both (251).
[VERTEBRATA-ACRANIA]
Free-living fish-like Chordata, but without skull, paired fins, or heart, and with colorless blood. Amphioxus (251).
SYNOPSIS OF THE ANIMAL KINGDOM 389
[VERTEBRATA-CRANIATA]
Free-living Chordata, with skull and complex brain, and red blood.
CYCLOSTOMI. Eel-like vertebrates without lower jaw, and living a parasitic life (245).
PISCES. Aquatic vertebrates with gills, without lungs, and with paired fins instead of legs. SELACHII, skeleton cartilaginous, no operculum, spiral valve (246). GAXOIDEI, skeleton either cartilagi- nous or bony, spiral valve and operculum present : sturgeons (247) ; spoon-bill (247); garpike (248) ; bowfin (248). TELEOSTEI, skeleton bony, no spiral valve. [ACAXTHOPTERI], dorsal, anal, and ventral fins with spines, pharyngeal bones distinct : perches (235) ; darters (234) ; sunfishes (235) ; toadfishes (236) ; sculpins (236) ; silversides (236) ; sticklebacks (238). [PHARYNGOGNATHI] fins with spines, pharyngeal bones united. [AXACANTHIXI], fins without spines, ventral fins far forward: codfishes (239) ; flatfishes (240). [PHYSOSTOMI], fins with- out spines, ventral fin placed far backward : smelts (230) ; trouts (233) ; whitefishes (234); catfishes (239); suckers (241); minnows (242); pikes (242); shads (243); eels (244). [PLECTOGXATHI], intermaxil- laries and maxillaries united. [LOPHOBRANCHII], body covered with bony plates : pipefishes (244).
AMPHIBIA (= Batrachia). Vertebrata having no lateral fins (but instead, legs) ; functional external gills during a part of their life. URODELA. Amphibia which retain the tail permanently: Sirenidce (255); Proteidce (257); Amphiumidce (257); Cryptobrancliidce (257); Amblystomidce (257); Plethodontidce (259); Desmognathidce (259). Pleurodelidce (254). AXURA, Amphibia which lose the tail in the adult stage : Pipidce (263) ; Hylidce (263) ; Bufonidce (265) ; Ranidce (265). GYMNOPHIONA, Amphibia which have no limbs nor tails; bodv worm-like.
«/
REPTILIA. Vertebrata which breathe exclusively by lungs and whose skin contains horny epidermal scales or bony plates. CHELOXIA, trunk enclosed in a bony case : Chelonidce (274) ; Trionychidce (274) ; Testudinidce (275). SAURIA, shoulder-girdle and sternum present, usually with eyelids : Chamceleonidce (272) ; lyuanidce (268) ; Varanidce (269); Lacertidce (270); Helodermidce (270); Ancjuidce (271). OPHI- DIA, footless scaled reptiles with no shoulder-girdle, sternum, nor
390 ZOOLOGY
movable eyelids: Colubridce (-76) ; Elapidw (277); Crotalidce ('277). CROCODILINA, large reptiles, with longitudinal vent (279).
AVES. Feathered Vertebrates. CURSORES, Aves with keelless sternum (307). NATATORES, swimming birds (305). GRALLATORES, wading birds (305). GALLINACEI, large ground birds with strong, perching feet and flat nails (304). COLUMBIN.E, short cloven feet and compressed nails (303). SCANSORES, birds with powerful beak and feet adapted for climbing (299). CYPSELOMOPH^, cereless birds, with scaleless metatarsus (301). PASSERES, birds whose metatarsus is covered with laminae or scales, usually with singing apparatus : Tyran- /</</«! (295); Aland idee (295) ; Corvine (294) ; Icteridce (293) ; Frincjil- lidce(284)i Tanagridce (292); Hirudinidce (292); Ampelidce (291); Laniidte (289) ; Vireonidce (288) ; MniotUidce (287) ; TrnglodtjtidcK (287); Certhiidce (286); Paridce. (286); Sylviidce (285); Turd idee (285). RAPTORES, birds with cere, hooked bill, and strong, hooked claws (298). PSITTACI, birds with cere, high, hooked beak, and fleshy tongue (parrots, 297).
MAMMALIA. Vertebrates which nourish the young by means of milk, and are usually covered with hair. MOXOTREMATA, oviparous mammals (321). MARSUPALIA, provided with a marsupium (322). EDENTATA, teeth either absent, rudimentary, or without enamel (323). CETACEA, marine hairless mammals, hind limbs absent (324). UNGU- LATA, hoofed mammals : even-toed ungulates (326) ; odd-toed ungu- lates (327); elephants (327). RODENTIA, canines absent, incisors grow continuously through life (320). CARNIVORA, canines large (328). INSECTIVORA, small, terrestrial, carnivorous mammals, with small canines (327). CHEIROPTERA, mammals with flying membrane between elongated digits (329). PRIMATES, with hands (329).
GLOSSARY
abdomen, in Arthropoda, the hinder- most of the three divisions of the body, 59.
aboral, the side of the body opposite to the mouth, 193.
alveolus, a depression, e.g. the socket of a tooth, 280.
angulated, forming an angle or sharp corner; opposed to rounded, 249.
antenna, horn or feeler, one of the anterior tactile appendages of Ar- thropoda and Mollusca, 4, 46.
anterior, situated at the front end of the body.
anus, the posterior opening of the food canal.
aorta, the main blood-vessel coming from the heart.
articular, relating to a joint; the hinge bone of the lower jaw of fishes, 232.
atripore, the external opening of the atrium, 249.
atrium, or vestibule, a chamber placed either in front of the mouth or, in Chordata, around the gill-slits.
auditory clubs, club-shaped sense or- gans on the margin of the bell of jelly-fishes, 221.
basihyal, a bone found in fishes, form- ing the base of the U-shaped arch which supports the tongue, 232.
bifid, two-parted.
bivalve, having two valves or shells, 131, 178.
blastula, a stage in the early develop- ment of the egg when it forms a hollow sphere, 193.
branchial, relating to the gills.
branchiate, bearing gills, 131.
branchiostegal rays, the bony rays supporting the membrane below the bones of the operculum in fishes, 232.
buccal, pertaining to the mouth cavity or cheeks, 59, 143.
bysxus, a tuft of tough threads spun from the foot of bivalves and used for attachment to foreign bodies, 180.
calcareous, consisting of a calcium or lime compound.
calcified, rendered calcareous by depo- sition of salts of lime.
callus, a soft substance secreted over a harder bony material, 175.
calyx, cup.
cambered, concave on the under side, 42.
canine, or canine tooth, the pointed tooth situated immediately behind the front cutting teeth, 331.
capsule, a little sac containing a fluid.
carapace, the thick shell or skin cov- ering the back of Crustacea or Che- Ionia, 103, 280.
cardinal, belonging to the hinge, as the teeth of lamellibranch shells, 188.
carnivorous, flesh-eating.
391
392
ZOOLOGY
cephalothorax, united head and thorax. cere, a waxy sheath at the base of the
bill of certain birds, 315. chelicera, the first pair of mouth ap- pendages in the Arachuida, 80. cilia, microscopic, vibratile processes
of certain cells. cirrus, a filamentous appendage of the
parapodia of Annelida, 159. cleavage, the multiplication of cells at
the beginning of the development of
the egg, 193, 336. clitellum, a thickened glandular ring
sometimes found in the earthworm. coxa, that joint of an Arthropod leg
which is nearest the trunk, 59. culmen, the upper ridge of a bird's bill. cuticula, the tough secreted "skin"
covering arthropods, hydroids, and
other animals.
dentary, a bone of the lower jaw of fishes which carries the teeth.
dextral, right, applied to right-handed shells, 166.
diaphragm, a dividing membrane, 119.
elytron, the horny upper wings of beetles, 59.
enamel, the hard covering of teeth and some fish scales, 248.
encyst, the act of secreting a cyst or vesicle, 227.
enteric, pertaining to the enteron or food canal.
epidermis, the outermost skin of ver- tebrates; also a superficial horny secretion over the shells of mol- lusks, 175.
epimeron, a lateral piece behind the episternum of insects, 59.
epiotic, one of the bones surrounding the inner ear in the lower verte- brates, 232.
episternum, a piece just lateral to the sternum in the thorax of insects, 59.
epistome, in beetles, a piece above the mouth, 59.
facetted, composed of numerous small eyes, making up a compound eye, 78.
femur, thigh of insects, 59.
fertilization, the union of two germ- cells, 335.
flagellum, a microscopic, lash-like, vibrating thread of certain Infuso- ria, 226.
foliaceous, leaf -like.
frontal, applied to a bone of the skull lying between the orbits, 232.
gastrolith, a calcareous nodule occur- ring in the stomach of the higher Crustacea, 103.
gastrula, a stage in development of the egg just after the digestive cav- ity has been formed, 193.
gastrulation, the process of forming the gastrula, 336.
gonad, a germ-producing gland, 221.
gonophore, a sexual zooid, generally reduced to an exclusively reproduc- tive function, 212.
gula, the throat plate on under part of the head of insects, 59.
hsemal, relating to the blood system.
hirsute, hairy, shaggy, 42.
hydranth, the "heads" or zooids of
ahydroid stock, 210. hyomandibular, a bone which, in
fishes, connects the lower jaw with
the skull, 232.
imago, the adult of an insect. intermaxillary, the same as premaxil- lary.
GLOSSARY
393
interopercular, the posterio-inferior opercular bone of fishes, 232.
jugal, the cheek-bone, 232.
keel, a ridge on the breast-bone of birds for attachment of flying mus- cles, 314.
labial, pertaining to the labium. labiitm, the under lip of insects, 59. Idbrum, the upper lip of insects, 59. lamella, a leaf or plate, 58. lamina, a thin plate. lancet cell, a lancet-shaped cell on the
hinder margin of the fore wing of
Phytophaga, 43. larva, an immature but active stage of
development, 10.
Ugula, the front edge of the labium, 59. liver area, in crabs, the anterio-lateral
area of the carapace in front of the
gill region, 123.
lumen, the central space of a tube. lunule, a crescentic or heart-shaped
area in front of the beak of some
bivalve shells, 190.
madreporic plate, in echinoderms, a
perforated plate admitting water to
the system of water tubes, 204. mandible, in arthropods, the most
anterior of mouth parts, 59 ; in
vertebrates, the bone of the lower
jaw. mantle, the fold of the skin of a mol-
lusk, or cirriped, which secretes the
shell, 160. manubrium, in jelly-fishes, the mouth
stalk, corresponding in position to
the clapper of a bell, 211. marsupium, a pouch, in Marsupalia,
on the ventral side of the body,
331.
maxilla, in Arthropoda, one of the mouth parts immediately following the mandible, 59 ; in vertebrates, a tooth-bearing bone of the upper jaw.
maxillary, relating to the maxilla.
maxilliped, one of the foot-like mouth parts which in arthropods follow the maxillae.
mentum, the front plate of the labium in insects, 59.
mesopterygoid, one of the bones form- ing the base of the skull in bony fishes, 232.
mesothorax, the middle segment of the thorax, 59.
metamerism, the fundamental repeti- tion of parts of the body along the longitudinal axis, as in earthworms 139.
metapleure, in Amphioxus, a latero- ventral fin, 249.
metapterygoid, one of the bones form- ing the base of the skull in bony fishes and lying behind the mesop- terygoid, 232.
metasternum, the ventral plate of the last thoracic segment of insects, 59.
metatarsus, in birds, the foot proper, 315.
metathorax, in insects, the third or last segment of the thorax, 59.
morula, an early stage of egg develop- ment when the germ consists of a nearly solid mass of cells, 330.
moult, to change the skin, as in in- sects.
myocomma, the thin layer separating two muscle plates in vertebrates, 246.
myomere, a muscle plate, 246.
nasal, belonging to or forming the
nose, as nasal bones. neural, pertaining to the nervous
system.
394
ZOOLOGY
neural groove, the groove which marks in the vertebrate embryo the devel- oping central nervous system, 261.
nodulous, covered with nodules or little lumps, 175.
notochord, the axial supporting rod of chordates, 249.
wsophaaus, the gullet, the part of the
food canal leading to the stomach. operculum, in gastropods, the horny
plate which closes the aperture ; in
fishes, the gill-cover, 232. oviduct, the duct which carries eggs
from the body, 120. oviposit, to lay eggs, as in insects, 53.
palatine, of the palate or roof of the mouth ; name of a pair of bones forming the palate, 232.
pallial line, streak formed in a bivalve shell by the margin of the attached mantle.
pallial sinus, an incurving of the pal- lial line to receive the siphon in cer- tain lamellibranchs.
palp, a secondary sensory outgrowth of a mouth part of an insect, 59.
paraylossse, a pair of small appendages of the under lip of insects, 59.
parapodia, the paddling feet of poly- chsetes, 147.
parasitic, living on the nutritive juices elaborated by another organism.
parasphenoid , a bone occupying the base of the skull, 267.
parietal, bones of the middle upper part of the brain case, 232.
pectinate, comb-like.
pectoral, of the chest ; the chest limbs of fishes, 246.
pedicellarise, minute forceps-like or- gans found on some echinoderms,
pelvic Jin, or ventral fin, the hinder
paired appendages of fishes, 246. penultimate, next to the last. percoid, like a perch. perisarc, the outer tough skin of hy-
droids, 211. pharynaeal, relating to the pharynx
or throat, 252.
polyp, the sessile form of coelenterates. posterior, situated behind. premaxilla, the most anterior tooth- bearing bone of the upper jaw of
fishes, 232. preopercular, the most anterior of the
bones of the operculum of fishes,
232. primaries, the large feathers on the
distal joint of a bird's wing, 315. proboscis, in insects, a sucking tube
connecting with the mouth, 61. prostermun, the most anterior of the
ventral plates in the thorax of in- sects, 59. prostomium, in worms, a lobe of the
body projecting above and in front
of the mouth. prothorax, the most anterior of the
segments of the thorax of insects,
59. pseudobranch, in fishes, a rudimentary
gill in front of the first throat slit,
231. pseudopodia, retractile processes in
Protozoa. pterotic, one of the ear bones of fishes,
232. pteryyoid, a bone of the base of the
cranium, 232. pupa, a stage in insect development
preceding the imago, 11.
quadrate, a bone lying between the skull and the hinge of the lower jaw in fishes, 232.
GLOSSARY
395
radii , lines proceeding from a common
centre like the spokes of a wheel,
86. ramus, a branch or projecting process,
131. rictus, the corners of the month in
birds, 315. rostrum, beak, the frontal process of
crustaceans.
scansorial, capable of climbing, 315.
scutellate, composed of plates, 315.
scittellum, the third of the four pieces composing the upper part of a tho- racic segment of an insect, 59.
septa, the radial calcareous plates of a coral, 215.
sinistral, left.
siphon, the drawn-out edges of the mantle folds of lamellibrauchs, 183; the strand penetrating the chambers of the Nautilus shell, also called siphuncle, 173.
spatulate, shaped like a spatula, or a paddle.
sphenotic, one of the bones forming the ear capsule of fishes, 232.
spinnerets, the tubercles through open- ings in which the spider thread is spun, 84.
spiracle, one of the openings to the air-tubes of insects, 59.
spurious, not genuine.
squame, a scale in decapods attached to the antenna, 124.
sternum, in vertebrates, the breast- bone, 280; in insects, the ventral part of a somite, 59.
stigmata, spiracles.
stock, colony, 207.
stolon, a runner from which zooids
bud, 220. subopercular, the lowermost bone of
the operculum in fishes, 232. suborbital, a bone in fishes, lying
below the eye, 232. supraethmeoid, a bone of the nose in
fishes, 232. supraoccipital, a bone forming the
upper part of the back of the head. suture, a seam or structural line, 70. symplectic, a bone uniting the quad- rate to the bones suspending the
lower jaw, 232.
tarsus, the jointed foot of an arthro- pod leg, 59.
telson, the tail-piece of a crustacean, 11(5.
tentacle, a projecting tactile organ.
thoracic, pertaining to the thorax or chest.
tibia, the joint of an insect's leg next above the tarsus, 59.
trachea, one of the respiratory tubes of insects, 64.
trjchanter, a joint of the insect leg lying distal to the coxa, 59.
umbilicus, a depression in the centre of the base of many spiral shells, 175.
umbon.es, a protuberance just above the hinge of a bivalve shell, 188.
velum, a circular membrane extend- ing like a shelf from the margin of the jelly-fish bell, 211.
viviparous, giving birth to well-de- veloped progeny, 331.
INDEX
Aardvark, 323.
Abnormalities, lobster, 119; plana-
rians, 155 ; starfish, 196. Acanthocottus, 236. Acanthopteri, 252. Acarina, 95. Acartia, 128. Accipiter, 298. Acineta, 225. Acipenser, 247. Acmaea, 170. Acmaeidae, 177. Acrania, 252. Acrididae, 1, 15. Actitis, 306. Adalia, 56. Adeorbidae, 175. Admiral, 21. ^Eschna, 10. Agalena, 90. Agricultural ant, 37. Alaudidae, 259, 317. Alligator, 279. Allolobophora, 114. Alosa, 243.
Amblystoma, 257, 335. Amblystomidae, 257, 267. Ameiurus, 240. American crossbill, 284. Amia, 248. Ammonites, 173. Amoeba, 227, 229. Ampelidae, 291, 317. Ampelis, 291. Amphibia, 254; distribution of, 255;
metamorphosis of, 260. Amphioxus, 249, 252. Amphipoda, 112. Amphitrite, 149, 150, 159.
Amphiuma, 198.
Amphiumidae, 257, 266.
Amphiura, 198.
Anacanthini, 253.
Anatis, 56.
Ancestry of vertebrates, 248.
Angle wings, 21.
Anguidae, 271.
Annelida, 136.
Anodonta, 191 ; embryo of, 180 ; food
of, 178 ; habitat of, 178. Anolis, 268. Auomiidae, 191. Anthremis, 48. Ant-eater, 322. Antelopes, 326. Authophagus, 47. Ants, 30, 34, 43; army, 37; colonies
of, 35 ; intelligence of, 35 ; language
of, 36 ; leaf-cutting, 37 ; social life of,
36.
Anura, 255, 262, 266. Apes, 230.
Aphaniptera, 61, 70. Aphids, 14. Aphrodite, 148. Aphroditidae, 159. Apidae, 31, 42. Aplysia, 164. Apteryx, 307, 308. Arachnoidea, 92. Arbacia, 200. Area, 184. Archaeopteryx, 314. Arched crabs, 123. Archiaster, 195.
Arcidae, 184. Arctiidae, 24, 41. Araneina, 80, 95. Argiope, 80-83, 86; 397
distribution of,
398
ZOOLOGY
83 ; food of, 82 ; spinning habits of,
82. Argouauta, 172.
Arion, 162.
Ark shells, 162.
Armadillo, 323.
Army ants, 37.
Army worm, 28.
Arthrogaster, 92.
Ascaris, 151.
Asilidae, 66.
Asiphonata, 178.
Asp, 277.
Asparagus beetle, 56.
Assassin bug, 12.
Astacidse, 124.
Astacus, 97-99, 113.
Astartidae, 190.
Asterias, 197 ; distribution of, 192, 197.
Asteriodea, 197, 203.
Astrangia, 216.
Atoll, 217.
Attus, 91.
Auriculidre, 161, 166, 176.
Autolytus, 147, 159.
Aviculidas, 185.
Axolotl, 258, 260.
B
Baboon, 330.
Badger, 328.
Balauinus, 53.
Balanoglossus, 250, 251.
Balanus, 129.
Bald eagle, 298.
Baltimore oriole, 293.
Banded horse-fly, 66.
Bark-borer, 53.
Barnacles, 102; habits of, 129.
Barn-swallow, 292.
Barrier reef, 217.
Bat, 329 ; food of, 329.
Batrachia, 254.
Batrachus, 236.
Bears, 328.
Beaver, 310.
Beaver parasite, 56.
Bee-moth, 29.
Bees, 30, 31, 42 ; swarming, 32.
Beetle, 44; development of, 44; eco- nomic importance of, 57 ; food of, 56 ; larval habits of, 45 ; number of species of, 45.
Bell-hydroid, 209.
Belted kingfisher, 300.
Birds, 281 ; economic importance of, 311 ; extinct, 313; flight of, 310; pro- tection of, 312; migration of, 309; teeth of, 314.
Bird's-nest, edible, 303.
Bittern, 305.
Black-fly, 66.
Black lobster, 103.
Black moccasin, 279.
Black snake, 276.
Blattidre, 8, 14.
Blister-beetle, 57. 61.
Blow-fly, 61.
Blue, 22.
Bluebird, 285.
Bluejay, 295.
Boa, 276.
Bobolink, 294.
Boll-worm, 28.
Bomb us, 31.
Bombycidrc, 24, 42.
Bombyx, 24.
Bonasa, 304.
Bony fishes, 252.
Bosminid*, 131.
Bot-flies, 64, 72.
Botryllus, 250.
Bougainvillea, 211.
Bowfin, 248.
Box tortoise, 275.
Brachiopoda, 127, 130.
Braohycera, 61, 63.
Brachyura, 107.
Branchipus, 127, 130.
Brittle-stars, 198.
Brook sucker, 241.
Brown creeper, 288.
Bruchidse, 57.
Bryozoa, 141, 217.
BucciuidsB, 175.
Buck-beetles, 54.
Budding, 217.
Buffalo gnat, 66, 72.
INDEX
399
Bufo, 264.
Bufonidae, 265.
Bugula, 142.
Bull-frog, 266.
Bull-head, 241.
Bullidae, 174.
Bumblebee, 31.
Buprestidae, 51, 60.
Buprestis, 51.
Buthus, 93.
Butterflies, 41 ; broods of, 17 ; habits
and food of, 16; mimicry of , 18-21;
polymorphism of, 17; protective
resemblance of, 18-21.
Cabbage butterfly, 18.
Callianassa, 105.
Callinectes, 109.
Calosonia, 46.
Calyptraeidae, 177.
Cambaroides, 99.
Cambarus, 99, 100, li;i.
Camels, 326.
Campanularian liydroids, 210.
Campanularidfe, 209, 221.
Camponotus, 35.
Canada grouse, 304.
Cancer, 114.
Carabidae, 45-46, 60.
Carchesium, 224; food of, 225.
Cardiidse, 190.
Cardinal grosbeak, 285.
Candidae, 124, 180.
Carolina paroquet, 297.
Carnivora, 328, 331.
Carpenter ant, 35.
Carrion-beetles, 48, 57, 60.
Carrion-fly, 73.
Case-bearers, 29.
Cassowary, .'507.
Catfishes, 239, 253; range of, 239-240.
Catocala, 19, 28.
Catometopa, 123.
Caudina, 201, 203.
Caviare, 247.
Cecidomyidae, 66, 68.
Cedar-bird, 292.
Cedar waxwiug, 291.
Centipedes, 74.
Centrums, 93.
Cephalopoda, 171.
Ceratodus, 249.
Cerambycidfe, 54, 56, 61.
Cerebratulus, 158.
Cerithia, 288.
Certhiidae, 286, 316.
Cestoda, 386.
Cetacea, 324, 331.
Ceuthophilus, 6.
Ceryle, 300.
Chameleo, 272.
Chameleon, 272.
Cheetah, 328.
Cheiroptera, 329, 331.
Chelidon, 392.
Chelonia, 273, 280.
Chelonidfe, 274.
Chestnut-sided warbler, 288.
Che wink, 285.
Chigger, 95.
Chigoe, 71.
Chilopoda, 74; food of, 74.
Chimney-swift, 302: nest of, 302.
Chimpanzee, 330.
Chipping-spar ro w , 2.S5.
Chiton, 171.
Chlorops, 72.
Choloepus, 324.
Chordata, 388.
Chrysomelidse, 57, 61.
Chrysops, 66.
Cicada, 13; pupal case of, 13.
Cicindela, 45.
Cicindelidae, 45.
Ciliata, 229.
Ciona, 250.
Cirratulidae, 159.
Cirratulus, 149, 159.
Cirripedia, 131.
Cistenides, tube of, 150.
Citheronia, 25-26 ; larvae of, 25.
Citigrada?, 89, 96.
Civet-cats, 328.
Cladocera, 127, 131.
Clam, 178.
Claws, abnormal, of lobster, 120.
Clepsiue, 140-141.
400
ZOOLOGY
Click-beetle, 61.
Clisiocampa, 26, 27.
Clothes-moths, 29-30.
Clymenella, 150-159.
Clypeaster, 201.
Cnidaria, 205; fresh-water, 207.
Cobra, 277.
Cobweb spiders, 80.
Coccinellidffi, 55, 61.
Cockatoos, 297.
Cockroaches, 8, 14.
Codfishes, 253 ; habitat of, 239.
Coelenterata, form of, 205.
Colaptes, 301.
Coleoptera, key to families, 58-61;
terminology, 59. Colonies, of ants, 35 ; formation of, in
Cnidaria, 217-218. Columba, 304. Golumbellidse, 176. Columbidae, 303. Columbines, 314. Columbridffi, 276. Condor, 298, 299.
Congo snake, 256 ; habitat of, 257. Con urns, 297. Cooper's hawk, 299. Copepoda, 127, 131. Copperhead, 279. Copris, 50.
Coral cup of Manicina, 216. Coral, polyps, 215-216 ; reefs, 216-
217.
Coregonus, 233. Cordylophora, 207-208. Corvidae, 294, 316. Cotton-worm, 28. Cow-bird, 293. Crab's eyes, 104. Crab spider, 89, 90, 96. Crane-flies, 68-69, 73. Cranes, 305. Craspedosomida3, 79. Crassatellidae, 190. Crayfish, 97, 122 ; development of, 117 ;
edible, 113; food of, 98; moulting
of, 103, subfamilies of, 98-99. Creepers, 286. Crepidula, 169-170, 177.
Cribrella, 196-198.
Crickets, 4-5, 15.
Cricket-grasshopper, 6.
Crinoidea, 203.
Crocodile, 279.
Crocodilina, 279-280.
Crossbills, 285.
Crotalidse, 277-278.
Croton bug, 8.
Crow, 294.
Crow-blackbird, 293.
Crustacea, 97, 104, 125.
Cryptobranchidse, 257, 266.
Cryptobranchus, 258.
Ctenophora, 219-220.
Cuckoos, 299 ; laying habit of, 300.
Culex, 68.
Culicidse, 68.
Cumacea, 122.
Curculionidae, 53, 61.
Cursores, 306, 315.
Cuttlefishes, 172.
Cyanocitta, 295.
Cycladidae, 180, 191.
Cyclas, 191; habitat of, 180; distribu- tion of, 180-181.
Cyclometopa, 123.
Cyclostomi, 252, habits of, 245 ; para- sitic on fishes, 245-246.
Cyclops, 127-128.
Cyllene, 54-55.
Cypselomorphae, 301, 315.
D
Daddy-long-legs, 93.
Daphnia, 97, 125; food of. 126; effect
of temperature on, 127. Daphnidae, 131. Darcus, 49.
Darters, 234, 252 ; habitat of, 234. Decapoda, economic importance of,
111 ; eyestalks of, 121. Deer, 326.
Degenerate flies, 7^. Dendroctonus, 53. Dermestida3, 48, 49, 61. Dero, 137, 144. Desmognathidas, 259, 267.
INDEX
401
Desmognathus, color of, 250; habitat of, 2<JO.
Development, of beetle, 44; crayfish, 117; edentates, 333; effect of heat on, 333; effect of light on, 333; of egg, 115; frog's egg, 332; fly, 62; general laws of, 335 ; grasshopper, 3-4 ; lobster, 115-117 ; Spelerpes, 261- 262; starfish, 193-194; Urodela,261.
Diapheromera, 7.
Didelphys, 323.
Diemyctylus, 267; food of, 254; hab- itat of, 254 ; life history of, 254-255.
Digger wasp, 34, 43.
Diplocardia, 143.
Diplopoda, 74.
Dipnoi, 248, 252.
Diptera, 61,63, 72; injurious toman, 71; scavengers, 72; short-horned, 63; source of disease, 71.
Discontinuous genera, 99-100.
Distomum, 155.
Divers, 60, 306.
Division of labor in Cnidaria, 219; physiological, 120.
Dodo, extermination of, 314.
Dogs, 328.
Dogfish, 246.
Dolphins, 324.
Doryphora, 55.
Downy woodpecker, 301.
Dragon-fly, 9-10.
Duckbill, 322.
Duck-bill catfish, 247.
Dytiscidae, 4(3, 56, 60.
Dytiscus, 47, 138.
E
Eagles, 298. Earwigs, 9. Earthworm, 132-134; economics of.
135; food of, 134; habits of, 132;
regeneration of, 134; relationships
of, 132 ; resistance of, 134. Echidna, 322. Echinarachnius, 201. Echinoidea, 322. Echinoids, 204. Echiurus, 139.
Economic importance, of beetles, 57; birds, 311; decapods, 111; earth- worms, 135; parasitic worms, 158; protozoa, 228; slugs, 162; starfish, 193; smelt, 230.
Ectopistes, 304.
Ectoprocta, 143.
Edentata, 323, 331.
Edentates, discontinuity of, 323.
Edible, birds' nests, 303; Carididae, 114; crabs, 108-109, 113; crayfish, 113; lobsters, 113.
Eels, 253; description, distribution, reproduction, 244.
Egg, fertilization, 336 ; masses of tent caterpillar, 26; nauplius, 115.
Egrets, extermination of, 305.
Elapidae, 277.
Elaps, 277.
Elateridae, 51, 61.
Elephants, 327.
Endoprocta, 143.
Enemies of lobster, 102.
English sparrow, 281; food of, 282; spread of, in America, 281-282.
Engraver beetles, 61.
Ensis, 182.
Entomophaga, 43.
Eutomostraca, 97, 125.
Eolis, 171.
Ephemeridae, 10.
Epiera, 80; web, 87.
Erycinidae, 190.
Euglena, 225-226, 229.
Euglycera, 146, 159.
Eunicidae, 159.
Eupagurus, 106.
Eupomatis, 235.
Eutamia, 276.
Even-toed ungulates, 326.
Exotic species, increase of, 283.
Extinct birds, 313.
Eyestalks of decapods, 121.
Falcons, 298. Fasciolariidae, 175, 177. Felis, 328. Fiddler crabs, 110, 123.
402
ZOOLOGY
Fireflies, 51-52, 58, 60.
Fishes, 230.
Fissurella, 170.
Fissurellidte, 177.
Flagellata, 225, 229.
Flatfishes, 239-240, 253.
Flatworms, 153.
Fleas, 61, 70.
Flicker, 301.
Flies, 61 ; degenerate, 70 ; development of, 62; food of, 62; plant-infesting, 72 ; mimicry in, 65 ; parasites of, 63 ; parasitic, 70 ; trachea of, 63.
Flight of birds, 310-311.
Flycatchers, 295.
Food of, beetles, 56; butterflies, 16; crayfish, 98; earthworm, 134; fly, 62; hydra, 207; mouse, 319; English sparrow, 282; starfish, 193; whale, 325.
Forficulidffi, 9.
Formicidse, 34-35, 43.
Fossil, birds, 314; lizards, 272; man, 331.
Fossoria, 34, 43.
Fowls, origin of, 305.
Fox-sparrow, 285.
Fresh-water clam, 178.
Fresh-water Cuidaria, 207.
Fresh- water jelly-fishes, 208.
Fringillidae, 284, 317.
Fringing reefs, 217.
Fritillaries, 22.
Frog, development of, 333; postem- bryonic development of, 334.
Frog's egg, development of, 332 ; heal- ing of, 334; regeneration of, 334; size of, 332.
Fulgur, 168, 169, 175.
Fundulus, 242.
G
Gadus, 239. Ganoidei, 247-252. Ganoids, 252. Garpike, 248. Garter snake, 27(5. Gasterosteus, 237-238. Gastropoda, 160, 161.
Gall-gnats, 66, 72.
Gall-flies, 31.
Gall-producing Hymenoptera, 43.
Gall- wasps, 31, 38-39.
Galls on plants, 67.
Galley-worm, 76.
Gallinacei, 304, 314.
Gallns, 305.
Gebia, 105.
Geese, 306.
Gelasimns, 110-111.
Genera, discontinuous, 99-100.
General laws of development, 335.
Geometridse, 28, 42.
Geomys, 320.
Geophilus, 76.
Geothlypis, 289.
Gephyrea, 138-139, 141.
Germ theory of Infusoria, 223.
Gibbous, 330.
Gila monster, 270-271.
Giraffes, 326.
Glossina, 65.
Glow-worm, 271.
Glyceridse, 159.
Gnats, 61.
Goat-suckers, 301, 303.
Golden-crowned kinglet, 287.
Gopher, 320.
Gorilla, 330.
Grallatores, 305, 314.
Grapta, 21.
Grasshopper, 1-4 ; development of,
3-4.
Grass spiders, 90. Gray-veined white, 18. Great horned owl , 299. Great northern shrike, 290. Green frog, 266. Grillidae, 4-5, 15. Grillus, 5.
Ground-beetles, 45-46. Grouse, 304. Gryllotalpa, 5. Guinea fowl, 304. Gulls, 306.
Gymnophioua, 255, 266, 389. Gypsy moth, 28. Gyrinidse, 46, 60.
INDEX
403
H
Habitat, of Anoclonta, 178; butter- riles, 1(5; Daphnia, 12(5; earthworms, 132 ; Hydra, 205 ; slug, 161 ; Uuio, 178.
Habits, of Acrididse, 1; mouse, 319; rat, 319.
Hadrosaurus, 273.
Hair streaks, 22.
Hairy ant-eater, 323.
Hairy woodpecker, 301.
Halistemma, 213.
Hard-shelled clams, 190.
Hares, 321.
Hawkbill-turtles, 274.
Hawk-moths, 22, 41.
Hawks, 298.
Heating of frog's egg, 334.
Heat, effect on development, 333.
Helicidae, 101.
Helix, 161-165 ; introduction of nemo- ralis, 164; variations in, 164.
Hellbender, 257, 258.
Heloderma, 270, 271.
Hemiptera, 12, 67.
Hen clams, 189.
Hermit crabs, 105, 107, 123.
Herons, 305.
Hessian-fly, 67, 68, 82.
Hesperornis, 313.
Heterandria, 242.
Heteroptera, 12.
Heterotricha, 224, 229.
Hippa talpoides, 107.
Hippidae, 107, 123.
Hippoboscidae, 70.
Hippopotamus, 326.
Hirudinidae, 292, 316.
Holothurians, 201.
Holothuroidea, 204.
Holotrichia, 229.
Homarus, 100, 113.
Homoptera, 13-14.
Honey bees, 32-33.
Horn-pout, 241.
Horned corydalis, 12.
Horned fly, 72.
Horned toad, 269.
Hornet, 34.
Horses, 327; fossil, 327.
Horse-flies, 65, 72.
House-fly, (il.
House wren, 288.
Humming-birds, 301.
Hydra, 205, 335; description of, 205-
207; food of, 207; habitat of, 205;
regeneration of, 219. Hydractiuia, 209. Hydrocorallidre, 208, 220. Hydroidae, 220. Hydromedusfe, 212, 220. Hydrophilidae, 60. Hydrophilus, 47. Hydrozoa, 220. Hyenas, 328. Hygrotrechus, 12. Hylidre, 263. Hymenoptera, 30, 72; gall-producing,
43 ; parasitic, 38, 43 ; plant-eating, 43. Hypotricha, 229.
Ichneumon flies, 30. Icteridffi, 293, 317. Idylia, 219. Iguanidae, 268-2(59. Importation of mouse, 318. Increase of exotic species, 283. Indigo bird, 285. Infusoria, 222, 229. Insectivora, 327, 331. Intelligence of ants, 35. Iphiclides, 18. Isopoda, 112.
J
Jay, 294.
Jelly-fishes, fresh-water, 208; life his- tory of, 210; salt-water, 208. Jigger, 71, 95. Jingle shells, 191. Julidae, 79. Julus, 76, 77, 79. Jumping mice, 321. Jumping spiders, 90, 91, 96, 321. June-bugs, 50.
Kallima, 20. Katydids, (5, 15.
K
404
ZOOLOGY
Key to classes of Echinodermata, 203 ; principal families of Acrididae, 2 ; Coleoptera, 58-01; Hymeuoptera, 42-43 ; Lamellibrauchiata, 188 ; Lepi- doptera, 41-42; Myriapods, 78; Or- thoptera, 14; Polychaeta, 159; Pul- monates, 161 ; principal genera of Daphnidae, 126; Laniellibranchiata, 191 ; to genus Lithobius, 79 ; to chief orders of Birds, 314-317; Entomos- traca, 130; Gastropoda, 100; Mala- costraca, 122 ; species of Earthworm, 143; of Lithobius, 79.
Killer whale, 325.
Killitish, habits, food of, 242.
Kingbird, 290.
Kingfisher, 300.
Kitchen-middens, 188.
Lacerta, 270.
Lacertidae, 270.
Lachnosterna, 50.
Ladybird beetles, 55, 61.
Lamellibrauchiata, key to families of, 188.
Lamellicornidae, 58.
Lamellicorn beetles, 49-50, 58 ; leaf- eating, 50 ; scavengers, 50.
Lamprey, 245.
Lamprey eels, 252.
Lampyridae, 51, GO.
Land-locked fishes, 230.
Language of ants, 36.
Laniidae, 289, 316.
Lanius, 290.
Larks, 295.
Larval habits, of beetle, 45; grass- hopper, 3-4 ; lobster, 116.
Laterigradse, 89, 96.
Leaf beetles, 61.
Leaf-cutting ants, 37-38.
Leaf-eating lamellicorns, 50.
Leaf-hopper, 44.
Leaf-miners, 42.
Leaf-rollers, 42.
Lecanium, 13.
Ledidae, 187, 188, 191.
Leeches, 139-140.
Lemurs, 329.
Leopards, 328.
Leopard frog, 266.
Lepidonotus, 147-148, 159.
Lepidosteus, 248.
Libinia, 108.
Life history, of mosquito, 68; Union- idae, 179-180.
Light, effect of, on development, 333.
Limacidae, 161.
Limacinidae, 177.
Limax, 161-164.
Limnaea, habitat of, 166.
Linmaeidae, 161.
Limpets, 170, 177; economic impor- tance of, 170.
Limulus, 114.
Line-weavers, 87, 96.
Liobunum, 93-94.
Lions, 328.
Lithobiidae, 78.
Lithobius, 74, 75, 78, 79.
Littorina, 167-108, 175; littoria, intro- duction, 107 ; range, 107 ; spread, 283.
Littorinidae, 175.
Liver-flukes, 153-154; life history of, 154-155 ; stages of, 150.
Lizards, 208 ; fossil, 272.
Llamas, 326.
Lobster, 100, 103, 113; abnormalities in, 119; development of, 115; em- bryos of, 110 ; enemies of, 102 ; moult- ing of, 103; protection of, 102.
Locust borer, 55.
Locusts, 14, 15; of old world, 2.
Locustidae, 1, 15.
Loligo, 172.
Long-horned beetles, 54.
Long-horned grasshoppers, 15.
Long-horns, 61.
Lophobranchii, 244, 253.
Lost parts, regeneration of, 118.
Louse-fly, 70.
Loxia, 284.
Lucanidae, 49, 58.
Lucanus, 49.
Lucius, 243.
Lumbriculidae, 144.
INDEX
405
Lycaenas, 22. Lycosa, 91. Lycosidae, 92. Lynceidae, 131. Lynx, 328.
M
Macaque, 330.
Macrodactylus, 50.
Macrolepidoptera, 22.
Mactra, 183.
Mactridse, 182, 189.
Maggots, rat-tailed, 65.
Malacostraca, 97, 111, 125.
Maldanidae, 159.
Mammalia, 318, 331.
Manatee, 324.
Mandrills, 330.
Mantidae, 8, 14.
Margaritana, 191.
Marmosets, 324.
Marsupalia, 322, 331.
Martens, 328.
Maryland yellow-throat, 288, 289.
May beetles, 50.
May-flies, 10.
Meadow grasshopper, 6.
Meadow-lark, 293.
Meal-beetles, 61.
Meal-worms, 52.
Mealy bng, 14.
Measuring-worms, 42.
Medusa, 211.
Megascops, 298.
Melampus, 161, 176.
Melanoplus, 2.
Meloidae, 61.
Melophagus, 70.
Metacrinus, 202.
Metallic wood-borers, 51, 60.
Metamorphosis, of Amphibia, 260 ; Ano- donta, 180; beetles, 44; crayfish, 117; dragon-flies, 9; fly, 63; frog, 335 ; Hemiptera, 12 ; Lepidoptera, 16 ; liver-fluke, 152 ; lobster, 116 ; Neu- roptera, 11; Orthoptera, 1 ; starfish, 194.
Metridium, 214, 215.
Microhydra, 208.
Microlepidoptera, 22.
Midgets, 62.
Migrations of birds, 309.
Milk-snake, 276.
Mimicry, 18-21 ; flies, 65.
Minks, 328.
Minnows, 242, 253.
Minyas, 214.
Mniotilidae, 287.
Mocking-bird, 287.
Modiola, 185.
Mole crabs, 123.
Mole cricket, 5.
Mollusca, 160, 178.
Monarch, 22.
Mongoose, 328.
Monkeys, 330.
Monotremata, 321.
Morone, 234.
Morula, 336.
Mosquito, 68.
Motacillidae, 317.
Moths, 22.
Moulting, 103.
Mourning cloak, 21.
Mouse, distribution of, 318 ; food of, 319 ;
habits of, 319; importation of, 318. Mud-daubing wasp, 82. Mud eel, 255, 256. Mud fishes, 252. Mud puppy, 257. Mud wasps, 34, 43. Muricidae, 169, 175. Mus, 321.
Muscidae, 61, 64, 72. Muskallunge, 242. Muskrat, 321. Musk turtle, 276. Mussels, 120, 190. Mustelus, 246. Mya, 182, 183. Myidre, 182, 189. Myrmica, 37. Mytilidre, 184, 190.
N
Naidse, 144. Nais, 137-138, 144. Narcomedusae, 221.
406
ZOOLOGY
Natatores, 305, 314.
Natica, 168, 175.
Naticidre, 175, 176.
Nautilus, 173.
Nebalia, 122.
Necturus, 257, 335.
Nemathelminthes, 386.
Nematocera, 61, 66.
Nematus, eggs of, 40.
Nemertini, 158.
Nephelis, 140.
Nereidae, 159.
Nereis, 136, 138, 145, 146, 159; food arid habitat of, 145.
Nest, of barn-swallow, 292; of chim- ney-swift, 302 ; of pewee, 296.
Neuroptera, 11-12.
Newts, 254, 362 ; how to capture, 255.
Night-hawk, 303.
Nightingale, 285.
Nile varan us, 269.
Noctuidse, 27-28,41.
Norwegian lobster, 113.
Notodelphys, 263.
Notolophus, 28.
Nuculidse, 191.
Nuthatches, 286.
Nymphs, 21.
O
Obelia, 210.
Odd-toed ungulates, 327.
Odonata, 9.
(Estridfe, 64.
Oligochreta, 132, 136, 139.
Oniscus, 112.
Operculura, of worms, 151; of fish, 233.
Ophiclia, 280.
Ophion, 39.
Ophiuroidea, 198, 203.
Opisthobranchiata, 161.
Opisthobranchs, 1(54, 170-171; degen- eration of shell of, 162.
Opossum, 322-323.
Orang-utan, 330.
Orbitelariae, 86, 96.
Orb-weavers, 86, 96.
Orbweb, diagram of, 86; of Epiera, 87 ; nomenclature of parts of, 86.
Orbweb spiders, 80.
Orca, 325.
Orchard oriole, 293.
Orchelium, 6.
Ornithorhynchus, 321.
Orthoptera, 1.
Orthosoma, 54.
Osmerus, 230.
Ostracoda, 127, 131.
Ostrea, 187.
Ostreid?e, 190; economic importance of, 187.
Ostrich, 307; habits of, 307-308.
Otter, 328.
Owlet moths, 27-28, 41.
Owls, 298.
Oxen, 326.
Oxyrhyncha, 123.
Oyster drill, 169.
Oysters, 187-188, 190.
Paddlefish, 247.
Paguridre, 105, 123.
Painted turtle, 276.
Palremonetes. 104.
Palinurus, 101.
Pallene, 95.
Palm-crab, 107.
Pandorida-, 189.
Pandorus, 23.
Panopeus, 109.
Papilionidre, 41.
Papilio,21.
Paramecium, 222, 229; food of, 224;
fusion of, 229; habitat of, 224; rate
of division, 229. Parasites of fly, 63. Parasitic, flies, 70; Hymeuoptera, 43;.
worms, 158. Paridse, 286, 316. Parrots, 297. Partridges, 304. Passenger pigeon, 303. Passer, 281-282. Passeres, 315.
INDEX
407
Patella, 170.
Pauropus, 77.
Pearl-bearers, 185 ; fishery, 185-186.
Peccaries, 326.
Pecten, 186.
Pectinatella, 143.
Pectinidfe, 190-191; locomotion of, 186.
Pedicellina, 141.
Pelicans, 306.
Perches, 235, 252.
Peritricha, 229.
Petrels, 306.
Petricolidae, 189.
Petromyzon, 245.
Pewee, 296; nest of, 296.
Pheasants, 304 ; range of, 305.
Phalangina, 93.
Pharyngognathi, 93.
Phasmidse, 7, 15.
Phasmomantis, 8.
Philampelus, 23.
Philinidae, 176.
Phoca, 328.
Pholadidse, 181, 188.
Pholis, 237.
Photuris, 52.
Phrynosoma, 269.
Physa, 161, 167; food of, 166; habitat
of, 166. Physalia, 213.
Physiological division of labor, 120. Physostomi, 253. Phytophaga, 43. Pickerels, 242. Pickerel frog, 266. Pieris, 21 ; rapae, increase and spread
of, 283. Pigeons, 304. Pigs, 336. Pike, 242. Pimpla, 37. Pin worm, 153. Pine borers, 53. Pinnotheres, 109-110. Pipa, 262 ; with embryos, 263. Pipe-fishes, 244, 253. Pipidffi, 263. Piranga, 293. Piroplasma, 228.
Pisidium, 191.
Pithecanthropus, 331.
Planarians, abnormalities of, 155 ;
fresh-water, 153; regeneration of,
154. Planorbis, 167; eggs and habitat of,
167.
Plant-eating hymenoptera, 43. Plant galls, 67. Plant lice, 14. Platyouichus, 110. Platypsylla, 56. Plectognathi, 253. Plethodon, 259. PlethodontidfB, 259, 267. Pleurodelidse, 267. Pleurotomidse, 176. Plovers, habitat of, 305. Plnmatella, 142. Plume-moths, 42.
Podophora, food and habitat of , 225. Podopthalmata, 122. Poisonous spiders, 91-92. Polistes, 33. Polychseta, 136, 148. Poly-cirrus, 149-150. Polydesmidse, 79. Polydesmus, 77, 79. Polymorphism in butterflies, 17. Polyphemidse, 131. Polyxenidre, 78. Polyzoniidae, 79. Pond snail, habitat of, 166. Portuguese man-of-war, 213-214. Postembryonic development of frog,
334.
Pouched gopher, 320. Prairie dog, 320. Prawns, 104, 124. Praying-mantis, 8, 14. Primates, 329, 331. Prionus, 54. Prosobranchiata, 160. Protection, of birds, 312; of lobster,
102.
Protective resemblance, 18-21. Proteidae, 257, 266. Protozoa, 222 ; relations to man, 228;
reproductive capacity of, 228.
408
ZOOLOGY
Psammobiidae, 189.
Psittaci, 297, 315.
Psoroptes, 94.
Pterophoridse, 42.
Pulex, 70.
Pulmonata, 160, 161, 164, 165; aquatic,
166.
Pumpkin-seed sunfish, 236. Pupa, 16, 165. Pupidse, 385. Pupipara, 61. Purple grackle, 294. Pyralidae, 29, 42. Pyramidellida?, 174.
Quail, 304. Quadrate, 232. Quiscalus, 294.
Q
R
Raccoons, 328.
Races of tame mice, 319-320.
Rails, 305.
Rana, 265.
Ranidae, range of, 265.
Raptores, 298, 315.
Rat, habits of, 319.
Rat-tailed maggots, 65.
Rattlesnake, 278.
Rays, 252.
Razor clams, 188.
Razor shell, 182.
Red-eyed vireo, 289-290.
Red-headed woodpecker, 301.
Reefs: barrier, coral, fringing, 217.
Redpoll warbler, 288.
Red-winged blackbird, 293.
Reduvius, 12.
Regal moth, 25.
Regulus, 287.
Regeneration, of earthworms, 134 ; flat worms, 153 ; frog's egg, 334 ; Hydra, 219 ; lost parts of lobster, 118 ; plan- arians, 154.
Relationships of earthworms, 132.
Reproductive capacity of protozoa, 228.
Reproduction, 332.
Reptiles, 268.
Resistance of earthworms, 134.
Retitelariae, 87, 96.
Rhea,307.
Rhinoceroses, 327.
Rhizopoda, 229.
Rice bird, 294.
Rissoidfe, 174.
Robber-flies, 65, 72, 73.
Robin, 285.
Rock-eel, 236, 237.
Rodentia, 320, 331.
Rodents, 320.
Rose-breasted grosbeak, 285.
Rose-bug, 50-51.
Round worms, 151.
Routes of bird migration, 309.
Rove beetles, 47, 57, 58.
Ruby-crowned kinglet, 285.
Ruby-throated humming-bird, 302.
Ruffed grouse, 304.
Runners, 60.
Running beetles, 45. .
Running spiders, 91, 96 ; habits of, 89,
S
Salmo, 233; skull of, 232. Salmonidae, 230, 231 ; distribution of,
231 ; spawning of, 231-233. Salamander, 259. Saltigradse, 90, 96. Sand dollars, 200-201. Sandpipers, 305. Sauria, 268, 280. Saw-fly, eggs of, 40; larvae, 39. Saxicavidffi, 189. Saxicolidre, 315. Scalariidae, 174. Scale bug, 14. Scale insect, 13 . Scaled worm, 148. Scallops, 190. Scaly ant-eater, 323. Scansores, 299, 315. Scaphandridfe, 176. Scarlet tanager, 293. Scavengers, Diptera, 72; Lamelli-
corns, 50.
Schizopod larva, 116. Schizoneura, 14. Scolopendra, 75, 76, 78.
INDEX
409
Scolopendrella, 78.
Scolopendridw, 78.
Scolytidse, 53, 61.
Screech owl, 298, 299.
Sculpin, 236, 252.
Scutigera, 75, 78.
Scutigeridse, 78.
Scyphozoa, 214,220.
Sea-cows, 324.
Sea-crayfish, 113.
Sea-cucumbers, 204.
Sea-lilies, 203.
Sea-lions, 329.
Sea-mats, 218.
Sea-mouse, 148.
Sea-spiders, 107.
Sea-squirts, 218.
Sea-urchins, 204; food and habitat of ,
199-200.
Sea-walnuts, 219. Seal, 328, 329. Searcher, 46.
Sedentary polychseta, 148. Selachians, 246. Selachii, 252. Semelidre, 189. Serpent stars, 203; description and
habitat of, 199. Serpula, 151, 159; tube, 151. Serpulidre, 159. Sertularia, 210. Sexton beetles, 48. Sexual dimorphism of spiders, 92. Shad, 253 ; range, 243-244. Sharks, 252.
Sharp-shinned hawk, 298. Sheep, 326. Sheep-tick, 70. Sheep scab, 94. Shipworms, 188. Short-horned diptera, 64. Short-horned grasshoppers, 51. Short-winged beetles, 47. Shrews, food of, 327. Shrike, 289. Shrimps, 104, 124; value of catch,
111.
Sididae, 131. Silk-worms, 42.
Silpha, 48.
Silphida3, 48, 60.
Silversides, 236, 252.
Simia, 330.
Simuliidse, 67.
Simulium, 67.
Siphonophora, 212-213, 220.
Siphonata, 178.
Siren, 255, 256.
Sirenia, 331.
Sirenidre, 255, 266.
Sitta, 287.
Sittidae, 316.
Skunks, 328.
Sloths, 323; two-toed, 324.
Slugs, 132, 160, 162; apparent absence
of shell in, 162; economics of, 162;
food of, 161-162; habitat of, 161;
species of, 162. Smelt, 230, 253; artificial propagation
of, 231 ; economic importance of, 230;
habitat of, 230; range of Atlantic
form of, 230-231 ; value of Atlantic
fishery, 231. Snapping beetles, 51. Snapping turtles, 275. Snipes, habitat of, 305. Snout beetles, 61. Snow-bird, 285. Snowy owl, 299. Social bees, 31. Social life of ants, Soft-shelled clams, Solaster, 197-198. Solemyidae, 189. Solenidas, 182, 188. Song-sparrow, 285. Song-thrush, 285. Sow-bug, 112. Spanish fly, 58. Sparrow-hawk, 299. Speckled tortoise, 276. Spelerpes, color of, 259; development
of, 261-262 ; habitat of, 260. Sphex, 82. Sphingidre, 22, 41. Sphinx moth, 23. Spiders, 80, 92; ballooning habits of,
83-84; classification of, 85; food of,
410
ZOOLOGY
82; poisonous, 91-92; sexual di- morphism of, 92; spinning habits of, 83; wandering, 88.
Spider-crabs, 107, 123.
Spider webs, economic importance of, 90.
Spinning habits, in spiders, 83.
Spiny ant-eater, 322.
Spiny lobster, 101.
Spirulidaj, 171.
Spizella, 285.
Sponges, 205.
Spontaneous generation theory, 223.
Spoonbill, habitat of, 247.
Spore of Infusoria, 223.
Sporozoa, 227, 229.
Spotted sandpiper, 306.
Spreading adder, 276.
Spring azures, 18, 22.
Square crabs, 123.
Squash bug, 13.
Squids, 171.
Squilla, 111.
Squirrel, 320.
Stable-fly, 61.
Stag-beetles, 49, 58.
Staphylinidse, 47, 58.
Starfish, 192,203; abnormalitiesof , 196; development of, 193-194; distribution and habitat of, 192 ; economic im- portance of, 193 ; food of, 193 ; larval stages of, 195; metamorphosis of, 195 ; systematic position of, 192.
Stentor, 229 ; habitat of, 224-225.
Sterna, 307.
Sticklebacks, 238, 252.
Stomatopoda, 111, 122.
Storks, 305.
Strongylocentrotus, 199.
Sturgeons, 247; economic importance, habitat, food of, 247.
Suckers, 241, 253.
Suctoria, 225, 229.
Sunfish, 235, 252.
Swallows, 292.
Swarm of bees, 32-
Swifts, 301, 302.
Sycon, 206.
Syllidse, 159.
Sylvicolidae, 317. Sylviidae, 285, 315, 316. Synapta, 202, 203. Synotus, 329. Syrphidte, 66, 73. Syrpus, 64.
Tabanidre, 65.
Tabanus,65, 66.
Tasnia, 157.
Talorchestia, 112.
Tanagers, 292.
Tanagridre, 292.
Tapeworm, 156; human, 157.
Tapirs, 327.
Tarantula, 92.
Teeth of fossil birds, 314.
Teleostei, 252.
Tellinidse, 190.
Tenebrio, 52.
Tenebrionidre, 52, 61.
Tent caterpillars, 26; egg masses of,
26 ; nests of, 27. Terebellidfe, 159. Teredidre, 181, 188. Teredo, 181. Termes, 11. Termites, 11. Terns, 306, 307. Terrapene, 275. Territelariffi, 85, 95. TestudinidaB, 275. Texas fever in cattle, 228. Thalassinidae, 105, 124. Theclas, 22.
Theridium, 80, 82; food of, 82. Thomisus, 90. Thrushes, 385. Tineidae, 29, 42. Tigers, 328. Tiger-beetles, 45. Tiger-moths, 24, 41. Tipulidse, 68-69. Titmice, 286.
Toadfishes, 252; habitat of, 236. Tornatinidfe, 176. Tortricidre, 29, 42. Toucans, 299.
INDEX
411
Trachea of fly, 63.
Tracheata, 387.
Trachina, 152, 153.
''"rachomed us<e , 221.
Jrap-door spiders, 86.
Tree-hoppers, 14.
Trematoda, 385.
Trepangs, economic importance of,
202.
Tree-sparrow, 285. Tree-toad, 265. Triangular crabs, 123. Triforidse, 177. Trilobites, 130. Trionychidre, 274. Trionyx, 275. Trochidse, 175. Trochilus, 302. Troglodytidse, 287, 316. Troglodytes, 288. Trouts, 233, 253. True bugs, 12. True wasps 83. Tsetse-fly, 64. Tube-forming worms, 102. Tube-weavers, 88, 96. Tnbifex, 136, 144. Tubificidse, 144. Tubitelarire, 88, 96. Tubularia, 208. Tubularian hydroid, 210. Tubularidaj, 208, 221. Tumble-bugs, 50, 57. Tunicata, 218, 251. Tunnel-weavers, 85, 95. Turbellaria, 385. Turdidae, 285, 315, 316. Turdus, 286. Turkey-buzzard, 299. Turkeys, 304; wild, 305. Turtles, 273; range of , 274. Tussock moth, 28. Twin-spotted sphinx, 23. Tyranuidfu, 295, 315. Tyraimus, 296.
Unau, 324.
Ungulata, 325, 331; even-toed, 326; odd-toed, 327.
Unio, 178, 191.
Unionidfe, 179, 180, 191.
Urodela, 255, 26(5 ; development of, 261.
Urosalpinx, 169, 175.
V
Varanida?, 269. Variations in Helix, 165. Veneridae, 180, 183, 190. Venus, 183. Vermetidre, 174. Vertebrates, ancestry of, 248. Vespa, 34, 35. Vesper sparrow, 285. Vesperidse, 43. Vespidae, 33. Vireo, 288, 290. Vireonidse, 288, 316, 317. Volvox, 226, 227. Von Baer's law, 336. Vorticella, 225, 229. Vultures, 298, 299.
W
Walking-sticks, 7, 15.
Wall-eyed pike, 235.
Walruses, 329.
Wandering spiders, 88.
Warblers, 285.
Wasps, 30, 33, 43; social, 33.
Water-dog, 257.
Water moccasin, 279.
Water scavengers, 60.
Water snakes, 271.
Water strider, 12.
Weasels, 328.
Weevils, 57.
Whales, 324; feeding habits of, 325.
AVhippoorwill, 303.
Whirligig, 60.
White ants, 11.
White-breasted nuthatch, 287.
Whitenshes, 234, 253.
White-lined horse-fly, 66.
White-throated sparrow, 285.
Wingless birds, 307.
Wingless cockroach, 8.
Wood-borers, 41.
412
ZOOLOGY
Woodchuck, 320. Wood frog, 266. Woodpeckers, 301. Wood-tortoise, 276. Wood-thrush, 286. Wood- warblers, 287. Worms, tube-forming, 102. Wrens, 287.
Xylotropidae, 23, 41.
Yellow bird, 285. Yellow warbler, 288. Yoldia, 187, 188.
Zebra, 327.
Zebra swallow-tail, 18. Zygsenidae, 41. Zygodactyla, 212.
A TEXT-BOOK OF ZOOLOGY
BY
T. JEFFERY PARKER, D.Sc., F.R.S.
Professor of Biology in University of Otago, Dunedin, N.Z.
AND
WILLIAM A. HASWELL, M.A., D.Sc., F.R.S.
Professor of Biology in the University of Sydney, N.S.W.
In two volumes, containing many illustrations
Cloth. 8vo. 2 vols. $9.OO, net
"The book deserves a warm welcome, and . . . will be found an •nvaluable aid not only to students of zoology, but also to a large num- .jer of those whose main interest lies in other branches of scientific study. Written with a clearness, accuracy, and method of a practised teacher, it is admirably illustrated with a profusion of figures — there are nearly twelve hundred in all — of the highest excellence."
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THE MACMILLAN COMPANY
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EXPERIMENTAL MORPHOLOGY
BY
CHARLES BENEDICT DAVENPORT, Ph.D.
Instructor in Zoology in Harvard University
PART I.
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— American Journal of Scienc
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