NOTES ON THE VICTORIAN SPECIES OF nrfJJXrS. 



15 V 



Charles Hehley, Assistant Curator. 

 (Plates MI.) 



Those fresli water snails once known in Australia as VJnj^^ti, hut now 

 referred to as lUillimni, have recentlj' acquii'ed an unpleasant interest. 

 For the spread and nui-ture of ha^niatura, a sevei-e, painful and incurahle 

 complaint, has recently' been tiaced to Egyptian lepresentatives of 

 ]>nJlhin><. 



The newly hatched embryo of a Treniatode, called r,ilJntr::ii(, enteis 

 the BnUi'iiiis snail and tliere turns into a spoi'ocyst. Then Bilharzid 

 cercariae are dischaiged from the infected snail every day for weeks, more 

 plentifully and continuously in summer. The fi-ee-swimming larva:^ swarm 

 on the suiface of the water in search of a victim. Should they fail to find 

 a host within forty-eight hours they must die. A successful pai-asife 

 enters the human body either by the mouth or through the skin, and 

 proceeds to establish itself in the lectum or bladder. Ai'rived at maturity, 

 the pai'asite slieds innumeiable hard-slielled eggs. These erode the 

 mucous membi-ane, thus causing internal bleeding, a symptom of tlie 

 disease. Victims may even die from necrosis of the liver or blockage of 

 poi'tal veins. 1 



It is presumed if tliis plague were to be introduced into the 

 Commonwealth fi-om Africa or Asia that the Australian species of ]hdU}iv>i 

 would be ready at any time or place to serve as an intermediate host and 

 so transmit it. Previously an Australian llnlliiiK^ had been indicted as 

 an intermediate liost for the sheep fluke. 



The genus thus acquires an importance for medical and official circles. 

 Hence the demand on Conchologists for exact determiiiation of these 

 shells and the present effort to improve the unsatisfactory current nomen- 

 clature and identification. 



In 1881, a Catalogue of Australian and Tasmanian Freshwater Shells 

 was published by Prof. R. Tate and Mr, J. Brazier.- They enumerated 

 fifty-four " Physa," more, as they point out, tlian half as many as were 

 recorded foi- the whole world. They remarked on the unsatisfactory and 

 indefinite knowledge of these species. In the following year, but without 

 acquaintance with his predecessor's paper. Mi-. E. A. Smith, of tlie Britisli 

 Museum, revised the Freshwater Shells of Australia. With additions 

 pioposed by himself he included fifty-two of " this neglected group " of 

 Australian "Physa;" •' but he thought that if his revision liad been inoie 

 complete, several species would be found endowed with a super-abundance 

 of names. 



1 R. T. Leiper— Proc. Rov. Soc. Medicme, ix., 1916, pp. 145-172. 



2 Tate & Brazier— Proc. Linn. Soo. N.S.Wales, vi., Dec. 1881. pp. 552-569. 

 ■' Smith — Journ. Linn. Soc. Zool., xvi., April, 1882, p. 275. 



