MAMMALIA. 



r. SEAL-EMBKYOS. 



REPORT ON A COLLECTION OF SEAL-E,MBRYOS {LEPTONYCIWTES 

 WEDDELLI) MADE DURINO THE VOYAGE OF THE ' DISCOVERY ' 

 IN THE ANTARCTIC SEAS, 11)01-1904. 



By H. W. :\Iarett Tims, .M.A. (Cantab.), M.D. (Edin.), 



Professor of Biologji, Royal Veterinary Cvllecje, and of Zoology and Comparative 



Anatomy, Bedford College {University of London). 



(2 Plates.) 



Introduction. 



Through the kindness of Professor Jeffrey Bell of the British Museum (Natural 

 History) a collection of seal embryos was placed in my hands for examination. The 

 collection was made during the voyage of the ' Discovery ' in the Antarctic polar seas 

 during the years 1901 to 1904. The bulk of the material was fairly well preserved, 

 though some was useless for histological purposes, while the larger specimens were so 

 brittle that it was scarcely possible even to dissect them. This, coupled with the fact 

 that the collection is rather deficient in early embryos, rendered it impossible to trace 

 out in detail the embryological history of these interesting animals. I have therefore 

 contented myself with giving a general account of the material, and of what appeared 

 to me to be the more salient points of interest, more particularly those connected with 

 structural adaptive modifications, or such as may have some bearing upon the phylogeny 

 of the .sub-order. 



The embryos are all labelled as those of Weddell's Seal (Leptonyehofes weddelli). 

 The material is the more interesting since a similar collection was obtained during the 

 voyage of the ' S. Y. Belgica' in 1897-1899. The latter has been placed in the hands 

 of several investigators, and some of their results have now been published. 



The Antarctic Phocidse are represented by five genera, Stenorrhynchus, Macrorhinus, 

 Luhodon, Ommatophoca and Leptonychotes* (syn. : Leptonyx, Poecilophoca), of which 

 the three last mentioned only are to be found within the Antarctic circle. 



Dr. Wilson (13) describes Weddell's Seal as being the most handsome of them 

 all, having a " coat richly marked with black and grey and silvery white ; the upper 

 parts are the darkest, but below the.se shades are blended in a most striking manner." 

 The adult animal measures 9 to 10 feet in length and has a girth of 6 to 7 feet. 



• The generic name, Leptonychotes, is now generally employed, since Sir William Turner pointed out that 

 the name Leptonyx had been pre-occupicd, having been given to other vertebrates as well us to a gastropod 

 mollusc : nee this Report, vol. ii., p. 10. 



VOL. V. B 



