vi RANINAE 251 



marked glandular complex on the top of the root of the tail, or 

 rather upon the future coccyx. These complexes gradually 

 disappear with age. 



The genus Rana, with about 140 species and sub-species, 

 is distributed over the whole of Arctogaea so far as this is 

 available for Amphibian life, while there are only a few stragglers 

 in Notogaea, namely, a few species in Ecuador and in the 

 Peruvian or Upper Amazon district. None exist in the rest of 

 the Neotropical region, including the Antilles, and practically 

 none in Australia; but R. arfaki and E. papua inhabit New 

 Guinea and the northern corner of Australia, R. kreffti the 

 Solomon Islands. A few species are restricted to Madagascar, 

 and a few others live there and on the continent of Africa. 



So far as number of species is concerned, the home of the 

 genus Rana is the Palaeotropical region ; about one dozen (some of 

 them with a very wide range) live in the Palaearctic sub-region, 

 scarcely more in the Nearctic sub-region, and a few in Central 

 America. 



R. temporaries (the common European Brown Frog or Grass- 

 frog). The tympanum is distinct, two-thirds the diameter of the 

 eye in size. The first finger is slightly longer than the second, 

 which is shorter and weaker than the others, whilst the fourth is 

 the longest. All the fingers are quite free. When the hind- 

 limbs are laid forwards along the body, the ankle-joint reaches to a 

 point between the eye and the tip of the snout. The five toes, 

 which are about half webbed, increase in length from the first to 

 the fourth, while the fifth is about equal to the third. The sole 

 of the foot has a small, blunt, inner metatarsal tubercle ; the outer 

 one is scarcely visible. The skin is smooth, always moist, owing 

 to the minute mucous glands ; but a series of larger glands forms 

 a pair of folds along the upper sides of the back ; beginning 

 behind the eyes they converge slightly beyond the shoulders, 

 diverge a little in the sacral region, and converge again towards 

 the vent. Another, much feebler, A-shaped ridge lies between 

 the shoulders. 



The male has two internal vocal sacs, which, when in use, 

 bulge out the skin of the throat beneath the angles of the mouth 

 like a pair of globes. It is further distinguished from the female 

 by the stronger muscles of the arms and by a pair of swollen 

 pads on the inner side of the first finger. During the pairing 



