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XXL — The Comparative Myology of the Shoulder Girdle and Pectoral Fin of 
Fishes. By. Captain E. W. Shann, B.Sc., Oundle School. Communicated by 
Professor W. C. MTntosh, F.R.S, (With Four Plates and One Figure in the Text.) 
(MS. received October 16, 1918. Read February 3, 1919. Issued separately September 26, 1919.) 
CONTENTS. 
PAGE 
Introduction 531 
The Study of Natural Groups of Fishes . . 532 
Generalised Comparative Survey (Table) . . 565 
PAGE 
List of Literature 566 
Index to Figures 569 
Description of Plates 570 
Introduction. 
Some months ago it was suggested that I should publish my thesis in its unfinished 
state. I refrained from doing so at that time, as 1 was unwilling to allow my work 
to appear until it was ready for publication. When it became apparent that the war 
might continue indefinitely. I decided to publish the thesis in such a form as the 
exigencies of the case would allow. 
For some years I had been fascinated by that elusive problem, the evolution of 
the pentadactyle limb of the higher Vertebrates. An extensive list of literature 
bearing directly or indirectly on this subject was gathered, and notes were made from 
upwards of a hundred monographs. It soon became clear that a necessary preliminary 
to the solution of the problem was a thorough knowledge of the limbs of fishes and 
their manifold modifications. The hind limb had been most ably handled by Davidoff 
as early as 1873, and the skeleton of the fore limb had been extensively treated by 
Braus, G-egenbaur, Owen, Parker, and others ; what still remained in a very unsatis- 
factory state was the musculature of the fore limb. Numerous authors had dealt 
with this latter subject, notably Braus (ll), Furbringer (31, 32, 33), Hamburger (42), 
Hartmann (44), Humphry (50, 51, 52), Jaquet (55), M‘Murrich (60), Marion (62), 
Owen (73), Tiesing (87), and Vetter (88), but few of these had treated it from the 
comparative standpoint ; moreover, the nomenclature was found to be so much at 
variance as to obscure probable homologies on the one hand, and, on the other, to 
suggest homologies where none in all probability exist. My object, then, became to 
elucidate the musculature of the fore limb of fishes. 
I am indebted to Professor Graham Kerr for specimens of Lepidosiren and 
Polypterus, and to Dr W. M. Tattersall for Periophthalmus ; the remainder of the 
types, with the exception of a few from my own collection, were generously placed 
at my disposal by Professor W. C. MTntosh, from the Zoological Department and 
Museum at St Andrews University. I also wish again to record my indebtedness to 
the Carnegie Trust, which provided me with the low-power Zeiss binocular microscope 
under which many of my dissections were carried out. 
TRANS. ROY. SOC. EDIN., VOL. LII, PART III (NO. 21). 
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