Mr. C. Hedley on the Range o/" Placost jlus. 435 



apex of the body, the venation longituduial. Abdomen with 

 the lateral margins produced and convex. Rostrum just 

 passing the anterior coxa3. Mesosternum wide ; a transverse 

 elevation between the intermediate and posterior coxjb, which 

 are situate close together. Abdomen beneath very flat and 

 depressed. Legs tiuclj setose. 



This is the first Australian genus of this division of the 

 Tessaratominee with which I am acquainted. 



Oarceusjidelisy sp. n. 



Pale uniform ochraceous. Antennae with the first and 

 third joints subequal in length, second joint longest. Pro- 

 notum and scutellum with an obscure central longitudinal 

 carination ; pronotura with a distinct fovea on each side of 

 the anterior area, the lateral margins laminately ampliated 

 and slightly recurved ; the whole disk obscurely transversely 

 wrinkled. Scutellum and corium thickly, obscurely, and 

 finely punctate. 



Long. 16 millim. j lat. prouot. angl. 8 millim. ; max. lat. 

 abd. 10 millim. 



Hab. Australia \ Peak Downs, in Queensland. 



LXX. — The Range o/Placostylus : a Study in Ancient 

 Geography. By C. Hedley, F.L.S.* 



The genus Placostylus appears a more fruitful subject of study 

 than any other molluscan genus inhabiting the same area. 

 Their large and handsome shells have attracted the attention 

 of the most superficial and unscientific collectors ; as a result 

 an extensive series of them have been brought to our know- 

 ledge from remote localities. Close and attentive scrutiny 

 would scarcely justify an observer in declaring that a parti- 

 cular minute shell did not inhabit any given island, whereas 

 a casual survey would decide whether a conspicuous shell 

 like Placostylus did or did not compose a portion of that 

 island's fauna. A larger mass of evidence, both negative and 

 positive, is therefore at our disposal in dealing with Placo- 

 stylus than awaits us in studying smaller species. 



The genus ranges from Faro Island, Solomons {P.founaki), 

 in the north, to Whangarei, New Zealand (P. bovinus), in 



* From the ' Proceedings of tlie Linneau Society of New South Wales,' 

 August 31, 1892. Coaimuuicated by the Author. 



32* 



