[Proc. Eoy. 8oc. Victoria, 22 (xN.8.), Ft. II., 1909. 



Art. XIV. — The Structure of the Tritncus Arteriosus 

 in Species of the geneva Hyla, Limnodi/nastes, Chir- 

 oleptes, Heleioporus, Psendophryne and Notaden, 



By KATHLEEN K. OLIVEK. 

 (With Plates XXXYII -XXXIX). 



[Read 9th December, 1909.] 



In reading various bioligical authorities I have noticed a 

 marked discrepancy in the different accounts of the number and 

 rehitive importance of the valves of the fi-og's heart. 



A. Milner Marshall and Ecker l)oth deal with Rana tempo- 

 raria, and each gives a different number of valves as guarding 

 ])oth the entrance to the Truncus Arteriosus froui the Ventricle, 

 and to the Synangium, from the Pylangium. 



Bourne, in his description of the frog, does not name the 

 species on which he is working, merely giving the generic name 

 of Rana, and differs again in regard to the number of valves 

 from both of the two above authorities. 



In the following account a description is given of the struc- 

 ture of the Truncus Arteriosus in representatives of the three 

 families of the Amphibia that are found in Australia. The 

 species examined are as follows : - 



Family Hylidae. 

 Hyla aurea. 



Family CystignatJiidae. 

 Limnodynastes dorsalis. 

 fieleioporus pictus. 

 Chiroleptes alboguttatus. 



Kamily Biijonidae. 

 Notaden bemietti. 

 Psoudophryne semimarmorata 



My thanks are due to Professor S])eni-cr for his kind help, 

 and for Ok- use of the la])oratory and dei)arlmcni specimens of 



