220 THE ZOOLOGIST. 



have not seen this bird, but I am told that a few are to be found 

 near Fishguard." Mr. Dix admits {torn. cit. p. 140) that his 

 observations were confined to a rather limited district, and that 

 many other species, particularly among sea birds, might be added 

 to his list. 



ON THE EXISTENCE OF TWO SPECIES OF AQUATIC 



FROGS IN NORTH GERMANY. 



By G. a. Boulenger. 



A SPECIES so widely distributed as Rana esculenta has naturally 

 given rise to the establishment of many so-called distinct " races " 

 or " species," but they have been founded on vague and trivial 

 characters, such as size, colour, roughness of the skin, &c. Of 

 late years the great variabilit}' of this species has caused all these 

 so-called forms to be thrown together, with the exception of the 

 oriental Rana marmorata, Hallow., which is regarded by Camerano, 

 Lataste, and myself as a distinctlj'^ recognizable form, whether 

 termed " species," " subspecies," or " variety." Quite recently 

 Camerano, in a valuable paper on the variations of R. esculenta 

 in the Mediterranean district,* has shown that distinct forms or 

 varieties, restricted to certain countries, may be grouped under 

 two jirincipal headings: — (i), those distinguished by a much de- 

 veloped inner metatarsal tubercle ; (2), those with a very feeble 

 inner metatarsal tubercle. The first group includes three varieties: 

 (1), viridis, Rosel, the typical form figured by Rosel, generally dis- 

 tributed in Central and Northern Europe, and found also in Italy ; 

 (2), lessonce, Cam., of Italy; (3), cachinnans, Pall., of E. Europe 

 and the borders of the Black Sea. The second group comprises two 

 varieties : (1), hcdr'iacjce, Cam., from Damascus; (2), latastii, Cam., 

 of N.E. Africa and Portugal. I need not enter now into the dis- 

 cussion of these races, as I reserve the subject for a future com- 

 munication. T will only add that, simultaneously with Camerano, 

 I drew attentiont to the variation of tliat same character of the 

 metatarsal tubercle, remarking that it corresponds pretty nearly 

 with tlie habitat ; but the material then at hand did not permit 

 me to insist upon that subject. My attention has been drawn to 



* Comptes Roudus de I'Asroc. Fiauc. x. (Congres d'Alger.), p.C80. 

 f Cat. Batr. Ecaud. Brit. Mus., pp. 'J, '68. 



