6E, 6F and 6G). In L. archeyi, however, even in specimens which are apparently sexually mature, only a relatively slight degree of ossification occurs (Figs. 6B, 6C, 6D and 6H).

Individual variation in fusion of the distal elements is very pronounced Typically, eight free carpal elements are observable, while the metacarpal of the prepollex is usually distinguishable In Fig. 6C, however, this metacarpal is fused with the adjacent carpal element In some cases, evidence has been noted of two apparent centres of ossification in the metacarpal of the prepollex, but in only one case, a specimen of L. hochstetteri, has a clear separation of a metacarpal element and a phalanx of the prepollex been noted Unfortunately, this condition was illustrated by the author in a previous paper (E. M. Stephenson, 1952, 610) and gives the impression of being the normal condition for the genus. It would appear from all specimens examined recently that a condition involving a separate phalanx of the prepollex is an uncommon individual variation of little significance. If this is the case, Bombina alone (Ridewood and Howes, 1888) among the Discoglossidae and Ascaphidae commonly possess a phalangeal element of the prepollex.

The simple, relatively small, and usually cartilaginous metacarpal of the prepollex of Leiopelma is far removed from the corresponding enlarged and specialised bony element of Ascaphus (Figures of Ritland, 1955, and personal observation).