[Proc. Koy. 8oc. Victoria, 21 (N.S.), Ft. I., 1908.] 



Art XI. — V(i rKit'iDiis in the Aixifijiii;/ of Hyla aurea- 



By GEOKGINA SWEET, D.Sc, 



Melbourne University. 



(With Plates XIX., XX.). 



[Rt'ad 9th July, 190S.]. 



A number of variations in the ni()q>hology of this form have 

 been already described (see Uibliograpliy), but one occasion- 

 ally comes across others, durinfr the dissection of the numbers 

 which pass through the hands of Junior Students in Biological 

 Laboratories. It is desirable that a record should be made of 

 these. Accordingly there are gathered together here the more 

 important of those noticed diu-ing the last few years in the 

 Biological Laboratory of the University of Melbourne. I wish 

 to thank Professor Baldwin Spencer, Dr. T. S. Hall and others 

 for directing my attention to variations which might not other- 

 wise have come under my notice. 



I. — Blood Vessels. 



fij. — Arteries. 



There have recently come under my notice three individuals 

 of this species, two of which (A and B) have 4 aortic arches 

 on either side instead of .3, as in a normal specimen, the third 

 (C) having 4 arches on the one side, but only .3 on the other. 

 One of these was found some years ago, one in 1907, one in 

 1908. In each (see Text figures 1-3) the additional arch lies 



Specimen A of Hyla aurea, 

 lijiviny four arterial arclies in 

 'he adult. 



1. Carotid arch. 



2. Systemic areli. 

 S. Vestiii'ial arch. 



4. Pulnio-cutaiieoii.s arch. 



F/o / 



