to provide a description and a reconstruction of the pectoral girdle of any species of Leiopelma A further outline description (E. M. Stephenson, 1952) was discussed by Ritland (1955) and two corrections, involving the position of the cleithrum and the shape of the suprascapula, were made by him. Ritland also described in more detail than previous authors the pectoral girdle of Ascaphus.

Pectoral girdles of the three species of Leiopelma are illustrated in Fig. 4. Comparing these with the diagrams of the pectoral girdle of Ascaphus (Ritland, 1955, 146), it is clear that in Leiopelma the clavicle does not extend so far laterally, relative to the scapula, as it does in Ascaphus.

The extent to which a procoracoid element can be identified varies with the species and from specimen to specimen within a species. It appears to develop and to ossify at a relatively faster rate in L. hochstetteri than it does in the other two species, in fact it seems probable that in L. archeyi and L. hamiltoni it does not ossify at all.

Fig. 4C illustrates the pectoral girdle of a mature male specimen of L. hochstetteri, in which the procoracoid is seen as an obvious bony element A similar condition, seen in external view, is illustrated in Fig. 3 in a previous publication (E. M. Stephenson, 1952, 607). No specimen of L. archeyi so far examined by the author has shown any trace of a procoracoid ossification and alizarin transparencies show no differential staining of the area in question (Fig. 4D) In specimens of L. hamiltoni examined, alizarin transparencies of two mature females and one old male show pink staining in the region where a procoracoid would be expected, but it has not been found as a discrete bony element.