88 



ON THE GENUS KRAUSSINA IN TASMANIA. 



By W. H. Twelvetrees and VV. F. Petterd. 



In 18o2 the late Dr. Davidson established the genus 

 Kraussia (whicli lie afterwards altered to Kraussina) for a 

 small terebratuloid hrMchiopod with diminutive arms and a 

 ver}'- insigiiificaut brachial support, consisting of two diver- 

 gent lamellae or lateral processes branching off right and left 

 from the median septum of the dorsal valve. The genus 

 now accommodates seven species, all recent, viz.: — 



Kraussina rubra, Pallas. Found off Natal and Port Eliza- 

 beth, South Africa. 



„ Cognata, Sowerhy. Found off Cape of Grood 



Hope. 



„ Deshavesi, Davidson. Found off Cape of Good 

 Hope, 120 iathoms. 



,, pisum, Valenciennes. Found off Cape of Good 



Hope, 150 fathoms. 



,, Davidsoni, Velain. Found at the Island of St. 

 Paul, low water mark. 



„ Lamarckiana, Davidson. Found at Port Jackson, 



N.S.W.; S.E. Australia ; New Zealand ; Mouth 

 of River Tamar and in Long Bay, Tasmania. 



„ Atkiusoni, Tenison Woods, h'ouud Long Bay, 



South Tasmania, 10 fathoms. 



Professor Deslougcha.mps has carried K. Lamarckiana and 

 K. Davidsoni over to a sub-genus Megerlina, possessing two 

 rudimentary septum processes underneath the calcareous 

 forks supporting the brachial (or more strictly speaking, 

 labial) appendages. 



The two Tasmanian species have engaged our attention. 

 The discovery of comparatively smooth individuals of what 

 appear to be K. Lamarckiana at George Town, near the 

 mouth of the Tamar, has suggested an inquiry as to whether 

 these really belong to that species, and if so, what are the 

 real differences between them and K. Atkinsoni. At the 

 time of Davidson's last monograph, the latter was regarded 

 as the sole smooth species of its genus. 



Kraussina lamarckiana is frequent at George Town and 

 between there and the Tamar Heads, at and below low water 

 mark, attached to rocus and large stones. Though the shells 



