BY C. HEDLEY. 881 



It will probably be found that closely allied but distinct species, 

 Gryptoplax striatus and C. guniiii for example, represent one 

 another on either side of the site of the Bassian Isthmus. 



West from Wilson's Promontory the coast-line included 

 between the lines of 65° and 55^ F. of minimum temperature is 

 more than four times the extent of that between corresponding 

 isotherms on the east. The endemic species of the Adelaidean 

 region may therefore be expected to exceed those of the Peronian. 

 So far as my studies have gone, this appears to be actually the 

 case. I have been struck by the high proportion of endemic 

 species among. the Diotocardia. And I am inclined to believe 

 that the range of species in space is usually more restricted in 

 the Diotocardia than in the Monotocardia. 



Our knowledge of tlie range of Australian marine mollusca is 

 brief, being almost limited to the neighbourhood of the chief sea- 

 ports. The compilation of lists of the fauna of intermediate 

 localities is much needed. A comparison between the fauna of 

 the east and west coasts of Tasmania should throw light on the 

 questions here discussed. 



In the following lists I have selected examples of species which 

 appear to characterise the two faunas under review. When the 

 attention of naturalists is drawn to this problem, I hope that 

 fuller lists not only of mollusca but of other groups may be 

 produced. 



Peronian. Adelaidean. 



Haliotis cocoradiata, Reeve. Lucapinella pritchardij Hedley. 



brazieri, Angas. Macroschisma producta, A. Ad. 



Callomphala lucida, Ad. & Ang. tasmanue, Sowerby. 



Liotia clathrata, Reeve. Haliotis albicans, Quoy &l Gaim. 



Astele scitulum, A. Ad. excavata, Lamarck. 



Calliostoma speciosuni, A. Ad. tricostalis^ Lamarck. 



Monilea bellida, Angas. emmce, Gray. 



pidcherrima, Angas. Liotia mayana, Tate. 



Cantharidus decor atus,Vh.\\i^^\. australis, Kiener. 



Clancuhcs omalomphabos, A. Ad. Aside subcarinata, Swainson. 



