Transcriber's note: Text enclosed by underscores is in italics (_italics_).
A single underscore introduces a subscript (CO_2), and a caret a
superscript (B^1).
Page numbers enclosed by curly braces (for example: {25}) have been
incorporated to facilitate the use of the Alphabetical Index and other page
references in the text.
* * * * *
THE
CAMBRIDGE NATURAL HISTORY
EDITED BY
S. F. HARMER, Sc.D., F.R.S., Fellow of King's College, Cambridge;
Superintendent of the University Museum of Zoology
AND
A. E. SHIPLEY, M.A., F.R.S., Fellow of Christ's College, Cambridge;
University Lecturer on the Morphology of Invertebrates
VOLUME VII
[Illustration]
HEMICHORDATA
By S. F. HARMER, SC.D., F.R.S., Fellow of King's College, Cambridge.
ASCIDIANS AND AMPHIOXUS
By W. A. HERDMAN, D.SC. (Edinb.), F.R.S., Professor of Natural History in
the University of Liverpool.
FISHES (Exclusive of the Systematic Account of Teleostei)
By T. W. BRIDGE, SC.D., F.R.S., Trinity College, Cambridge; Mason
Professor of Zoology and Comparative Anatomy in the University of
Birmingham.
FISHES (Systematic Account of Teleostei)
By G. A. BOULENGER, F.R.S., of the British Museum (Natural History).
London
MACMILLAN AND CO., Limited
NEW YORK: THE MACMILLAN COMPANY
1904
_All rights reserved_
_Third Fisherman_.—Master, I marvel how the fishes live in the sea.
_First Fisherman_.—Why, as men do a-land,—the great ones eat up the
little ones.
_Pericles_, Act II. Scene i.
{v}PREFACE
Owing to unforeseen circumstances, not unconnected with the foundation of a
new University, the publication of this volume has been unduly delayed.
Some parts of the work have actually been in type for more than four years;
and although the authors have made every effort to keep them up to date,
the arrangement is naturally not quite what it might have been if the
articles had been written immediately before publication.
In view of the novelty of Mr. Boulenger's classification of the
Teleosteans, and of the fact that several independent workers have been
occupying themselves with the subject during the last year or two, it is
fair to state that this part of the volume was completed in 1902. Professor
Herdman's account of the Ascidians was ready for publication two years
earlier.
Professor Bridge wishes to express his best thanks to Dr. R. H. Traquair.
F.R.S., for his kindness in reading the proofs of the pages which deal with
the fossil Crossopterygii, Chondrostei, Holostei and Dipnoi, and for much
helpful advice and criticism; to Mr. G. A. Boulenger, F.R.S., for his
valuable and suggestive criticism on certain points; and to Mr. Edwin
Wilson, for the care which he has taken in the preparation of the figures.
_July 1904_.
{vii}CONTENTS
PAGE
PREFACE v
SCHEME OF THE CLASSIFICATION ADOPTED IN THIS BOOK xi
HEMICHORDATA
CHAPTER I
CHORDATA AND VERTEBRATA-HEMICHORDATA-ENTEROPNEUSTA-EXTERNAL
CHARACTERS AND HABITS-STRUCTURE-GENERA-DEVELOPMENT-PTEROBRANCHIA-
_CEPHALODISCUS_ AND _RHABDOPLEURA_-PHORONIDEA-_PHORONIS_ AND
ACTINOTROCHA-AFFINITIES OF THE HEMICHORDATA 3
TUNICATA