388 *he zodLOGisi\ 



present, it is evident that these colonies become fewer and further 

 between as we descend from the north. I presume Transylvania 

 marks, so far as is yet known,* the limit of its southern extension. 



In Baden it has been cited from various points of the Rhine 

 Valley, — Manhheim, Freiburg, — and I was fortunate in coming 

 across a new settlement near the village of Eggenstein (about 

 four miles north of Karlsruhe), where this species occurs in great 

 abundance, together with R. esculenta and fusca. The locality is 

 a swampy depression in the otherwise well-cultivated fields 

 between the village and the Rhine woods, more or less flooded in 

 spring by a small stream running through the centre, while in 

 summer the ground is usually dried up. Though I have never 

 found arvalis far beyond the precincts of this, I have no hesitation 

 in predicting that it will turn up duly in many of the similar 

 tracts along the upper Rhine Valley. 



The coloration has been so often and admirably described, 

 that I will only note a few points with reference to these indi- 

 viduals from Eggenstein. As I have elsewhere observed, f the 

 striking appearance of the four light- coloured longitudinal fascia? 

 is more common with the females and young, while the males 

 incline to uniformity of tints. Still, one may also see young and 

 females plainly-coloured, as well as distinctly-striped males ; and 

 these dimorphic types, though most pronounced in their extremes, 

 are connected by an unbroken series of gradations. The delicate 

 blue or purple complexion of the males is subject to some 

 variation in degree, being naturally most intense with those 

 individuals which possess that flaccid and loose appearance due 

 to the distention of the lymphatic vessels. As may be expected, 

 it is most pronounced on the throat, though visible also along the 

 sides and back. It gradually vanishes towards the beginning of 

 May, when the other peculiarities of the nuptial costume are in 

 retrogression. The fore legs of the male, whose functions are 

 analogous to those of the hinder legs in lizards, are, like these, 

 disproportionately thickened, and the animals appear at this 

 season even more swollen than R. fusca, on account of their 

 slighter build and more pointed snout. The yellow of the sides 

 and hind legs is often very brilliant even with the young, princi- 



* V. Mehely, 4 Zool. Anzciger,' 1890, p. 445. 

 f ' Zoologischer Garten,' 1889, p. 221. 



