THE GEOGRAPHICAL DISTRIBUTION OK 

 QUEENSLAND GASTEROPODA. 



By JOHN SHIRLEY, D.Sc, F.M.8. 



(Senior Inspector of Schools.) 



Read before the Royal Society of Queensland, June 27th, 1913 



The number of aquatic gasteropods, reported as inhabit- 

 ing Queensland waters, amounts in all to 1,619 species 

 Mr. Charles Hedley published a list* and supplementf 

 of 1328 species ; and, in papers read before this Society, 

 the writer has supplied lists containing 291 additional 

 names. 



A study of the geographical distribution of these 1619 

 gasteropods has revealed some interesting facts. One of 

 the most striking is the similarity of the molluscan faunas 

 of the Indian and Pacific Oceans ; no less than 520 Queens- 

 land species, or nearly one-third of the whole, having this 

 extremely wide range. It, therefore, seems likely that the 

 two oceans have been in free and uninterrupted connection 

 for many geological ages, since many species, which are 

 at home in both oceans, belong to such genera as Turbo. % 

 TrochusX and Phasianella, known to extend back to Devonian 

 times ; others as Haliotis, Nerita, Litorina, Strombus, 

 Triton, (Cymatium), Dolium (Tonna), Sigaretus, Mitra, 

 Cancellaria and Murex° to Cretaceous times ; while Liotia, 

 Terebellum, Ranella, (Bursa), Marginella, Engina and 

 Purpura date from the Eocene epoch. Very few genera, be- 

 longing to the two oceans in common, appeared later than 

 the Miocene era. 



*Proc. Aust. Assoc, Vol. XII., pp. 343-371. 

 fLoc. cit., pp. 809-810. 

 JTryon, Vol. I., p. 57, says " Silurian." 

 °Tryon, Vol. I., p. 57, says " Jurassic." 



