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X. — Report upon the Anatomy and Embryology of the Penguins collected by 

 the Scottish National Antarctic Expedition, comprising : (1) Some Features 

 in the Anatomy of the Penguin ; (2) The Embryology of the Penguin : A 

 Study in Embryonic Regression and Progression. By D. Waterston, M.A., 

 M.D., F.R.C.S.E., and A. Campbell Geddes, M.D. (From the Laboratory of 

 the Anatomical Department, The University, Edinburgh.) (With Three Plates.) 



(MS. received March 11, 1909. Read February 3, 1908. Issued separately October 21, 1909.) 



Among the specimens collected by the Scottish National Antarctic Expedition and 

 brought back to this country was a series of the embryos of penguins of various species, 

 collected at different stages of development by Mr R. N. Rudmose Brown and Dr J. H. 

 Harvey Pirie. These embryos were, for the greater part, of the species Gentoo 

 (Pygoscelis papua, Forst.), the remainder of the species Adelia (Pygoscelis adelice, 

 Hombr. and Jacq.). Two Emperor penguins, which had been preserved for examination 

 by the injection of the blood-vessels, were also brought home. Through the kind- 

 ness of Dr W. S. Bruce these specimens were entrusted to one of us (D. W.) for 

 examination and report, but as the work involved in this proved to be very 

 extensive, Dr A. Campbell Geddes was asked to undertake a share in it, and this 

 he agreed to do. 



This report contains the results of the combined investigations. 



PART I. 



ON THE ANATOMY OF THE ADULT PENGUIN. 

 Introductory. 



Upon the return of the Challenger Expedition to this country, the late Professor 

 Morrison Watson had handed over to him the valuable collection of adult penguins 

 which had been made. Upon these he based his classical memoir, " A Report on the 

 Anatomy of the Spheniscidse collected during the Voyage of H.M.S. Challenger" 

 {Challenger Reports, vol. vii. p. 1). To that report little, if anything, can be added. 

 There are, however, two points which a detailed dissection of the adult penguin has 

 brought to light, which seem to us to be worthy of being placed on record. These are, 

 first, the peculiarities of the cervical portion of the vertebral column ; second, some points 

 in connection with the arrangement of the fascial layers- in relation to the pectoral 

 muscles. In all the other points illustrated by our dissections we can merely corrobo- 

 rate the description given by Professor Watson. 



TRANS. ROY. SOC. EDIN., VOL. XLVII. PART II. (NO. 10). 33 



