BY J J. FLETCHER. 669 



value of the amount of the webbing as a generic and specific 

 chai'acter; and he adduces instances of variation in the amount 

 in tlie same species ( C hiroleptes platijcephalus, and Hehiopoi ns 

 pictus ). I have also pointed out a similar state of things in 

 Mixophj'es. Similar variations are presented by Hyla ccurnha 

 and H. peroiin, as, for example, when specimens from the moist 

 subtropical Northern River Districts are compared with others 

 from the drier inland districts. Dr. Glinther and Mr. Boulenger 

 have allowed for variation in this respect in some of their descrip- 

 tions. Dr. Griinther says of Pelodryas (H. cceruleaj, " fingers 

 one-half or one-third webbed " ; and of H. peronii, " fingers one- 

 fourth webbed. Mr. Boulenger says of the latter, " fingers half- 

 webbed or nearly so, " though even this is an insufficient margin; 

 and of H. rubella, " fingei's free or with a slight rudiment of web; 

 toes two-thirds or three-fourths webbed." H. evmigii is simply 

 another addition to the list of species in which the amount of the 

 webbing of the fingers and toes is not a constant quantity. When 

 allowance is made for this, then //. krfifftii falls into, what I 

 believe is, its proper place as the eastern coastal representative 

 of the typical form of //. ewingii. If If. ewingii may comprehend 

 var. orienta/is, which is less webbed, it would obviously be illogical 

 to exclude a variety (var. kreffiii) because it tnay be a little more 

 webbed; for according to the B.M. Catalogue (2nd ed.) //. krpfftii 

 is "very closely allied to H. ewingii, but differing in the more 

 distinct wel) between the fingers, and the more extensive web 

 between the toes, it reaching the discs of the third and fifth." 



The difficulty in the way of finding a satisfactory general 

 expression for a quantitative estimation of the web is that all the 

 digits, and sometimes the two sides of the same digit, are not 

 relatively equally webbed, and also that their unwebbed ^Dortions 

 are or may be fringed, the true web then being reinforced by the 

 fringe if well developed. It is thus to some extent a question of 

 whether fringe is to count as web. If so, but not I think other- 

 wise, then in some specimens of var. krefftii, as Mr. Boulenger 

 says, the webbing may extend to the discs of the 3rd and 5th 

 toes, or more often only to that of the 5th That being so, how- 



