1885.] 



GERMAN RIVER-FROG. 



(i69 



nearly smooth. The glandular lateral fold is moderately prominent 

 and constantly broad, as broad as or even broader than the upper 

 eyelid. The coloration is tar less variable than in the typical 

 11. esculenta. In the normal condition the ground colour of the 

 upper parts is olive or bronzy-olive, with the vertebral band, the 

 fore limbs, and the sides of the head and body pale green or pale 

 olive. But, of course, through the play of the chroinatophores, the 

 same individual may pass successively from a very light to a very 

 dark hue, according to its being placed in very dry or very moist 

 surroundings. In specimens long kept in the water, the colour 

 turns to a very dark bronze-olive, almost blackish, in which case the 



c d *> 



a, h. S. ridibunda, Berlin ; c. B. esculenta, Berlin ; d. E. esculenta, 

 Basle ; e. B, esculenta, Diisseldorf. 



normally darker markings may assume a brighter greenish tint ; but 

 if these markings are examined with a magnifying glass, they are 

 seen to be black beautifully powdered with gold. The vertebral 

 band varies considerably in width, and may be absent altogether. 

 The glandular lateral folds are usually not conspicuously lighter- 

 coloured, though sometimes metaUic bronzy. The spots on the back 

 and flanks are more or less numerous, and the hind limbs are trans- 

 versely banded, but these markings are of a blackish-olive or bronzy- 

 brown, and never of an intense black as is frequently the case in 

 R. esculenta. The dorsal spots sometimes form pretty regular 

 longitudinal series, but are never confluent into longitudinal bands. 

 A dark canthal and supratemporal streak is usually present, and the 

 latter portion sometimes expands into a regular tem.poral spot. The 

 edge of the upper lip is either spotless or with a series of blackish 

 spots which very seldom unite to form a labial streak. The cross 

 bands on the legs may be very irregular or absent. The hinder side 

 of the thighs, i. e. that part which is concealed by the legs when the 

 animal is at rest, are whitish or pale greenish marbled with dark 

 olive or bronzy, or of the latter colour with or without small light 



