anterior to the heaks slopes away 

 markedly In Victoria il is conlincd 

 to a lew coastal rivers of east GipjJS- 

 land. where it is not common, anil 

 CJCtCnds up the coast of N.SAV. to 

 southern Queensland. Average length 

 50 mm. 



t ig I Vslcsimio unibiKuus. 



biu. I Hyinlvllu Ulyridelta) cfraptta. 



ffg, 3 Hsrulfllu (l>'<>u>h?iul,-U<i) 

 (•Irnelgcnsis. 



iliraui! |«| Mix, RWylli. Plant) 



326 



llvriikllu (H>ridelliO dnipela 



(Iredalc-, 19.34) 



This species is intermediate b e . 

 tucen the previous (wo species hut ]t 

 separated from them Ivy Us elongifo 

 ovale shape, the llalleneil pDSfflffe] 

 ridgeS and the delicate beak sculpture 

 I his is the commonest and mo v 

 widespread species of the genus m 

 Victoria being found faulv alum 

 danllv in most coastal livers and 

 siicams of the central and eastern 

 part of the State: also in some rhfCTJ 

 in the Otways area Outside Victoria 

 il is also found in the coastal rivers 

 of N.SAV. and southern Queensland. 

 Average length SO mm. 



Ilyrhlellii (Htridilla) iianaeaiKusis 



(Cotton and Gabriel. I'M?) 

 I his has a small shell with ., flfe 

 tinclive almond-shaped outline .m,l | 

 small, very strong hinge. II is con, 

 lined lo coastal riveis of cential and 

 eastern Victoria, and the Tatnar 

 River system in northern TttflUnn| 

 Average length t() mrn. 



Hyridella fJProtoh^dcBal cimdycnuis 



(Dennant, I.H9K) 



This highly distinctive species g 

 placeil in a different siih-genus from 

 all other species of the genus in Vic- 

 toria because ol its small size, the 

 strong shell sculplure. and exccplion- 

 ally strong hinge. It is almond shaped 

 and is winged posteriorly with a 

 prominent posterior rulge 



This species appears to be con- 

 fined lo the Cilenelg-Wanium user 

 system or I'ar western Victoria, Avet 

 age length 30 mm. 



Ki 1 1 Ki.scr 

 McMichael, D. F. and I. D HiiCocJl 

 1958. A Monograph of the frch 

 u.ik-i mussels (MbUusctt PoJecypoda] 

 at the Aii-.itaii.iii Region, 4w« J 



Mar. Fresh*. Res 9: 372-507. 



Vict Nat Vol 88 



