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Show 504 PROF. HOWES AND MR. A. M. DAVIES ON THE [DeC. 4, stand alone among Anura in the life-long retention of the inter-phalangeal syndesmoses. f. PELOBATIDiE. Examined :- Pelodytes punctatus, 39 millim. Xenophrys monticola, 48*5 millim. In Xenophrys the syndesmoses are feebly represented. That of the terminal joint is complete and ventrally enlarged, but reduced and feebly ligamentous in its middle. The fibres of the latter portion (/., fig. 8) pass from the distal face of the penultimate phalanx obliquely upwards and forwards, to he inserted into the proximal face of the terminal one. It will be obvious that there is here an approximation towards the condition of the inter-articular ligament of the Ranidce and Hylidce; and this species is particularly interesting as showing that there is no leading modification undergone by the proximal syndesmoses for which a counterpart cannot be found in the terminal one. The syndesmoses of the proximal joints are annular and largely absorbed, exhibiting traces of the inter-articular ligament of the above-named families. Pelodytes, the affinities of which with this family have been called into question1, while most nearly Pelobatoid, shows, with respect to its proximal syndesmoses, a tendency towards a condition intermediate between the Pelobatidce and Discoglossidce ; for these, while more independant of the apposed surfaces of the phalanges than in the Discoglossidae, are still imperforate. B. AGLOSSA. Examined:- Pipa americana, adult 8 • Xenopus Icevis, adult $ . The terminal joint of the hind limb was alone examined in each case. It was found to consist, in both genera, of a coarsely fibrous syndesmosis, showing no trace of special differentiation and most nearly suggestive of the condition seen in Pelodytes. C. URODELA. Examined :- Molge cristata, 135 millim. M. palmata (larvae), 25 millim. M. waltlii, 175 millim. Proteus anguinus, 135 and 220 millim. Salamandra atra, 130 millim. <S. maculosa, 140 millim. Spelerpes fusca, 130 millim. In this Order the syndesmoses are throughout uniform in structure ; 1 Cf. this vol. p. 125. |