12 PLEISTOCENE MAMMALIA. 



without adding any fresh arguments. Jukes (1864) (47) described some indentations 

 on limb-bones, which he believed could only be produced by a cutting instrument ; 

 but Carte, in the discussion on Jukes's paper, attributed the indentations to pressure 

 and friction, and in 1867 described bones from Lough Gur showing indentations 

 which he thought due to the same cause. Ball (1885) and Ussher allude to the 

 occurrence of long bones split as if for the extraction of marrow, in association with 

 stone implements in Ballynamintra Cave, co. Waterford. Adams, in 1878, stated 

 that none of the bones showed that man or beast preyed on the animal, and in 1880, 

 in his paper on " Recent and Extinct Irish Mammals " (73), expressed the belief that 

 there was no valid evidence showing the contemporaneity of Megaceros with Man in 

 Ireland. Later in the same year, however, he changed his opinion, and in a communi- 

 cation consisting of preliminary notes by himself and Ussher, recorded the occurrence 

 at Shandon of implements made from the undoubted bones of Irish Giant Deer. A 

 year later (1881), in describing the bones from Ballynamintra Cave, co. Waterford, 

 he recorded (76) the finding in association with hammerstones of bones of Megaceros 

 split as if for the extraction of the marrow, and stated that it could scarcely be doubted 

 that the regularity of fracture was due to their having been split for the purpose. 

 An examination of these bones, which are now in the National Museum at Dublin, 

 and comparison with others in the same collection, lead one to doubt whether the 

 splitting may not be due merely to the natural processes of weathering and decay. 

 Similar split bones have been found in the Clare caves. There is some evidence of 

 the co-occurrence of Man and Megaceros in the Isle of Man, and in England Megaceros 

 bones have been found associated with human remains at Kent's Cavern, Torquay, 

 while in France it was constantly hunted by Man. 



Some of the more recent writers on the subject have believed in its survival to 

 a late date. Thus, Sir H. H. Johnston (106) was of opinion that it probably lasted in 

 Ireland to the end of the Neolithic period, J. G. Millais (112) that it may have 

 become extinct only in Recent or Prehistoric times. He alludes to a skull in his 

 possession in the forehead of which is a deep cut, evidently made by a hatchet. 



g. Possible Causes of the Extinction of the Irish Giant Deer. 



A long succession of writers, ranging from Molyneux (1697) to Sir H. Johnston 

 (1903), have discussed this question, and the following suggestions have been made : 



1. That dense herds of these big animals may have been attacked by some 



microbial disease. 



2. That human hunters perhaps by pits, perhaps by huge drives, which sent 



herds over precipices or into bogs, were the chief cause. 



3. That its disappearance is due to a change in climatic conditions. 



4. That its extinction is due to over-specialization in structure, possibly 



leading to sterility. 



