112 RANAD^E. 



of a different kind. It is somewhat remarkable that my 

 father, who was no systematic naturalist, but a very ac- 

 curate observer, should have detected, when a boy, now 

 more than eighty years since, the distinction of the har- 

 vest mouse and of this species of Frog. The peculiarity 

 in the croak of the male is accounted for by the existence 

 of the large vocal sacs, to which farther allusion will be 

 made. 



The Rana esculenta may be at once distinguished from 

 R. temporaries by the absence of the large distinct black 

 mark, which in the latter species occupies the space ex- 

 tending from the eye to the shoulder, and by the existence, 

 in the present species, of a light line running the whole 

 length of the middle of the back ; the marbling also in 

 R. esculenta is much more distinct, varied, and beautiful, 

 and consists partly of circumscribed round spots. The 

 vocal sacs, which are peculiar to the males, become, when 

 filled with air in the act of croaking, large globular, blad- 

 der-like sacs, standing out one on each side of the head, 



which do not exist at all in R. temporaria : the vomerine 

 teeth are placed rather farther back in the common species. 

 I have observed in R. esculenta a pair of lumbar glands, 

 which, although less conspicuous, occupy the same position 

 as in the genus Pleurodema of Tchudi. 



