268 THE ZOOLOGIST. 



only prove that it has existed in England for the last 150 years ; 

 nothing more. 



Wolley's opinion that it may have been introduced by Italians 

 as a delicacy (as is said to have been the case with the Edible 

 Snail) was a mere suggestion ; still, as we shall see further on, it 

 is one which agrees with the facts I have now to bring to light. 



As to the third opinion, I may observe in the first place that, 

 as regards the colony at Foulmire Fen, it is hardly admissible 

 that a few hundred specimens having been turned out in widely 

 separated spots in Norfolk in 1837, and 1840, so many should 

 have migrated to a fen on the southern border of Cambridgeshire 

 to such an extent as to be found there in great abundance in 

 1843. But there is another much more important argument 

 against this view, which brings me to the object of this commu- 

 nication. 



The Edible Frog is a widely distrilnitcd form, and like all 

 such forms shows a great amount of variation, so that it is 

 possible to define several local races, or subspecies. One of the 

 safest characters for the division of R. esculcnta into minor 

 groups is afforded by the relative development of the inner meta- 

 tarsal tubercle. As I have observed in a previous communication 

 in this Journal (p. 220), the typical li. esculcnta as commonly 

 occurring in Central Europe has this tubercle compressed, large, 

 measuring 4 to 5 mm. in specimens in which the inner toe, 

 measured from the tubercle, averages 9 to 11 mm. On 

 examining the six specimens from Foulmire Fen in the British 

 Museum, I was much surprised to find that they do not agree 

 with the typical U. esculcnta, but differ in having the metatarsal 

 tubercle much larger still, shovel-shaped, with almost cutting 

 edge ; in the largest specimens the inner toe measures only 

 7 or 7| mm., and the tubercle gives 4 or 4^ mm. They therefore 

 cannot be ranked with the true R. esculenta, but belong to the 

 Italian form named by Camerano Rana esculcnta lessonce. Having 

 received, through the kindness of my friend Dr. Camerano, type- 

 specimens of the latter form from Piedmont, I have convinced 

 myself that there cannot be the slightest doubt that the British 

 Edible Frog belongs to the Italian form. Having informed Prof. 

 Newton of my discover}', he courteously enabled me to examine 

 two specimens from Foulmire, preserved in the Museum of the 

 University of Cambridge, and these also proved to be R. lessuua. 



