646 MESSRS. RITCHIE AND McINTOSH ON [Juiie 16, 



recognition both of his carrying out of the present exploration, by 

 which our knowledge of the Mammals of the Far East is being 

 steadily revolutionized, and of the fact that his own personal 

 acquaintance with the Cervidce and his wonderful collection of living 

 Deer at Woburn have been the basis of much of the considei-able 

 ncrease in our knowledge of the group which has taken place of 

 recent years. 



" A common deer about the edges of the forest at Chao-Cheng- 

 Shan. They were to be seen at all times of the day in groups of 

 two to five. Rarely were they solitary. During one long tramp 

 I saw fourteen in the day." — M. P. A . 



2. On a Case of Imperfect Development in Ecliiims escu- 

 lentus. By Jabies Ritchie, M.A._, B.Sc, The Rojal 

 Scottish Museum, and D. C. McIntosh, M.A., B.Sc, 

 F.R.S.E.* 



[Received May 7, 1908.] 

 (Plate XXXIII.t and Text-figures 138-142.) 



The description of abnormalities is of special value when these 

 are of unusual character and occur in a species little liable to 

 deviation from the type. Moi-eover, there has not hitherto been 

 I'ecorded any case of the special degree of abnormality illustrated 

 by our specimen. Therefore it is that M^e venture to set down 

 these observations, in spite of the fact that it seems impossible 

 to account with certainty for the origin, or even to determine 

 precisely the status, of the abnormality (whether it should be 

 regarded as an example of congenital variation, or simply as a 

 case of ari-ested development due to functional disturbance of the 

 organism by some external factor). 



The specimen, an example of the most common British Sea- 

 Urchin {Echinus esculentus Linn.), for which we are indebted to 

 Dr. A. Bowman, of the scientific staff of the Scottish North 

 Sea Fishery Investigations, was obtained by him, in July 1907, 

 in Basta Yoe, Shetland, where it was trawled from a depth of 

 twenty-four metres. In a note regarding it Dr. Bowman says : — 

 " The malformed Urchin occurred amongst a number of typical 

 ones. Unfortunately I took no notice at the time of any pecu- 

 liarity in the living animal. . . . The sport was not noticed until 

 the spines etc. were nearly all cleared off. I thought at first it 

 was an unusually flat variety." 



Description of Specimen. 

 (a) General Descri2}tion — Shape, Symmetry, d-c. 



At first sight the specimen appears to be, as Dr. Bowman had 

 noted, merely a rather flat variety, with a large oral surface and 



* Communicated by F. A. Bathee, D.Sc, P.Z.S. 

 t For explanation of the Plate, see p. 661. 



