654 



DESCRIPTION OF A FO.S.SIL LORICA FROM NORTH- 

 WESTERN TASMANIA. 



By A. F. Basset Hull. 



[Mollusc A : Polyplacophora j 



(Plate xvii., tig.s. 1-2.) 



LORICA DUNIAXA, U.sp. 



One example of median valve. 



Shell elevated, carinated, deeply decussated throughout. 

 Lateral areas: stiuiigly raised, ornamented with four,' increasing 

 at the sutural edge to seven, radial rows of large flattened pustules. 

 A well defined row of ocelli follows the front ridge of the area. 

 Central area: longitudinally ribbed with about 25 strong nodulose 

 ridges, with broad iiiters|iaces gradually increasing in width 

 towards the insertion-plates, and diminishing in height over the 

 jugal tract. Dimensions : width 25 mm. 



Insertion-plates are missing, but theie is an indication of one 

 slit. 



Remarks. — This species is allied to L. affini'^ Ashby and Torr,* 

 but is distinguishable from that species by the wider interspaces 

 in the central area, and the larger pustules and number of rows 

 on the lateral areas. It is also allied to the living species, L. 

 voli'ox Reeve,(New South Wales, South Australia, etc.) but differs 

 from that species in the number of ribs on the central area, and 

 the distribution of pustules. 



This fossil Chiton was collected by Mr. W. S. Dun, from the 

 base of the Turritella Sandstone, at the foot of -a bluff between 



* Ashby, E., and Torr, W. G., " Fossil Polyplacophora from Eocene Beds 

 of Muddy Creek, Mornington (Schnapper Point) and Moorabool, Victoria. 

 Trans. Roy. Soc. of South Australia, 1901, p. 137, pi. iv., fig. 7. 



