190 



ANURA 



CHAP. 



other, differing only in small points, for instance in the extent 

 of the webs to the fingers and toes, the configuration of the 

 vomerine teeth, the size and appearance of the tympanic disc, 

 and the relative length of the hind-linihs. In some of the West 

 Indian, and in one Brazilian species, H. nigromaculata, the upper 

 surface of the head is rough, owing to the cutis being involved 

 in the cranial ossification. Bony or perhaps only calcareous 

 deposits in other parts of the skin are rare, but are notably 

 developed in H. dasynotus of Brazil, in which they extend from 

 the head to the sacrum, rendering tlie skin immovable. 



Many are capable of changing colour to a great extent, and 

 it is a popular error to suppose that all tree-frogs are green. 



•rQ.SD 



Fig. 37. — Hijla arhorea, var. ineridioncdis. South European Tree-frog, x 1. 



although this colour is perhaps the most common in the arboreal 

 kinds. 



H. arhorea. — The tongue is rather round, slightly nicked 

 behind, and can be protruded but little. The tympanum is dis- 

 tinct, but small. The upper parts are grass-green, quit(? smooth 

 and shinv owim,^ to the skin beintj covered with a film of 

 moisture ; the under parts are yellowish-white and granular, flesh- 

 coloured or rosy on the thighs. Total length of large females 

 2 inches. This, the Tree-frog of Europe, has an enormous 

 range, namely, from Morocco, France, and the south of Sweden, 

 across the whole of Europe and Asia Minor to Japan and 

 Southern China. 



