Victorian Non-marine Molluscs 

 No. 5 



In 



Brian J Smiiii* 



Two species of large operculate 

 Freshwater gastropod? ;uv included in 

 the VJqKjriun In virtue of then 

 occurrence in the River Murray L f 1 1 

 like most of our non-marine gastro- 

 pod? (which are advanced molluscs 

 with a hint; and Lire therefore termed 

 pulmonalcs), these two species ate 

 more primitive in ancestry and more 

 closelv related to the marine gastro- 

 pods than to the other freshwater 

 forms. They are easily recognised hy 

 the presence of an oval disc of hornv 

 material on their '"tail" which forms 

 a sort of "front door" on the shell 

 w hen the animal retreats into it I Ins 

 is the operculum, and the animals 

 can therefore he termed opcrculatcs 

 A series of small black operculates 

 which inhabit coastal streams and 

 lakes will be the topic for a later 

 article. However, two large unrelated 

 species inhabit the whole ol the 

 MUTTS)/ Darling River Basin and ma\ 

 gfttetld into northern Victoria in some 



I'loliopsis halimiiviisis il (ima.l. INmii 



I his is an elongate, spiral shell 

 about 25 mm in length which varies 

 in colour from olive green to a daik 

 greeny brown with dark red or hrown 

 streaks and dots. It has distinct spiral 

 sculpture on the shell, and in most 

 specimens a series of raised ridges 

 or nodules occur on the shoulder of 

 each whorl. In large specimens the 

 ape\ or protoconch of the shell is 

 often broken olT. Little is known of 

 its way of life. It belongs to the 

 family Thiaridac. 



272 



\<>lii|>ala lumli'vi 1 1 i aiienleUI. 186J] 



This is a laige. solid. glohti| a . 

 shell with a length of about 25 mij. 

 It has a dark green to brownish perm- 

 stracum with a microscopic scutptun 

 ol granose lirae. The animal is com- 

 inoii in the mud ol iiwis and inhahih 

 ihe Mui-rav-Oarling Basin. Othei 

 species in the genus live in Queenv 

 land anil ihe Northern Territory. Hjj 

 animal is unusual in that it keeps jft 

 eggs in Us bodv wheie they hatch 

 the voting being born alive. Thh 

 species belongs to the fannlv \i\ 

 pandac. 



' ' ii i .11' 1 1 al lnv.il.hi.il.'. N,i.. n,l MuM'.m, „ 



\ ul.l.l.l 



Vict Nal Vol 86 



