910 OK THE ANATOMY OF THE PELOBATID/E. [Nov. 2C),, 



differentiate tliem fi'om AIegalo2)Jirys vwviana, but not from 

 Meg(dophr7/s vasnta. Megalophrys lonyipes^ has a, V-shaped fohl 

 upon the nape which recalls that of Xenophrys monticola, and not 

 that of Meyalophrys montana. 



A more satisfactory investigation of these various forms might 

 perhaps break down the distinctions which I have endeavoured 

 to set up between the four Oriental genera, and show that 

 Asterophrys and Bctirachojjsis are to be placed with them. In the 

 meantime, however, it is quite clear that the structure of the 

 Pelobatida?, as far as we know it at present, is quite in harmony 

 with the geographical range of the different forms. There is no 

 doubt that the four genei-a discussed here, which occur in the 

 Oriental region, are much nearei- together on the whole than any 

 one of them is to Pelobates, which is Pakearctic in range. It 

 would apjDeai- also that the American Scaphiojms is qiiite as 

 widely removed from either group, so far as we can judge from 

 the osteological characters accumulated by Mr. Boulenger f. It is 

 important to have been able to emphasise this relation betAveen 

 structure and geogi-aphical distribution. 



(6) Affinities of the Pelobatid.e. 



A number of features, chiefly to be found in the hyoid and the 

 fvised saci-al vertebi'te, by reason of which the Pelobatidne resemble 

 the Aglossa, and especially Pipa, have been brought together by 

 Dr. Bidewood J. I am able in the present communication to 

 add a few points of likeness between these two, at first thought, 

 very dissimilar groups of Anura. It must be remembered, how- 

 ever, that the existing knowledge of the Anura is in so very 

 rudimentary a condition that the following points of likeness 

 between the Pelobatida? and the Aglossa, though they are, as I 

 hope, accurately stated, may not be confined to the Pelobatida? ; 

 future dissection may show them to apply equally to other 

 families or genera among the Phaneroglossa. In view of the fact 

 that the Aglossa are an especially aquatic race, the members of 

 which rarely leave the water, and are not capable of active pro- 

 gression upon the land, features of- structui'al resemblance 

 between them and the Pelobatidfe in the muscles of the leg are 

 not Avithout interest, for they can be hardly put down to a mere 

 physiological caiise. As far as I am aware, the Pelobatidfe ai'e 

 not as a family especially aquatic in theii' habits. 



With regard to the hyoid, I can extend the facts dwelt upon 

 by Dr. Ridewood as evidence of approximation in structure to 

 the Aglossa ; for in certain of the Asiatic Pelobatidfe there is the- 

 same tendency towards a union of the anteiioi- processes of the 

 bod}^ of the hyoid. As an absolutely new point of likeness 

 between the Pelobatidfe and the Aglofsa, may be pointed out the 

 condition of the most posteriorly lying Petrohyoideus muscle. 



* Boulenger, P. Z. S. 1885, p. 850. f P- ^- S. 1899, p. 792. 



X Jnuvn. Linn. Soc. xxvi. 1897, p. Ill &c. 



