271 



them both at Lunawanna and Woodbridge, in the D'Entre- 

 casteaux Channel, and I took one on the Sandford Beach, 

 Frederick Henry Bay, and Mr. May has taken them at Little 

 Norfolk Bay and Port Arthur, all in southern Tasmania. 

 Tlie chitons were found on the sides of rocks that could only 

 be reached at lowest tide and are almost always covered with 

 a dense growth of algae, the removal of which requires the 

 greatest care, or the delicate "oar-headed" spicules will be 

 broken off. In addition the sculpture is often hidden under 

 calcareous growths. 



Variation. — The series shows a very wide divergence in 

 sculpture. The specimen selected as type may be considered 

 as an example of the most extensively sculptured variety, 

 and those from Port Arthur the extreme in the opposite 

 direction. The Port Arthur shells, while they have the two 

 strongly-raised lateral ribs, exhibit nothing of the flattened, 

 elliptical pustules of the more sculptured form, beyond slight 

 undulations. The space between the two ribs is smooth and 

 free from sculpture. The same absence from sculpture is 

 commpn to the pleural and dorsal areas, but the ray ribs 

 of the anterior valve are well raised and give a little evidence 

 towards the outer margin of the pustulose character. Inter- 

 mediate forms, between the highly-sculptured type and these 

 almost unsculptured specimens from Port Arthur, occur both 

 at Little Norfolk Bay and in the D'Entrecast^aux Channel, 

 but most give some evidence of flattened, broad, wavy ribbing 

 in the pleural area which I have likened to ripple marks. 



In conclusion. — Owing to the variable character of the 

 sculpture in different specimens I have had more than 

 ordinary difficulty in determining the constant specific differ- 

 ences that distinguish this species from the Marino and other 

 South Australian shells. It is possible that we have living 

 in South Australian waters two species, for the highly- 

 carinated specimen I collected at Port Lincoln, and referred 

 to in my paper (Trans. Roy. Soc. S. Austr., vol. xliii., 1919, 

 p. 71), was treated so roughly in scrubbing off the growth 

 that none of the delicate spicules are left, and it is impossible 

 at present to link it with either K. matthewsi, Iredale, or 

 the Tasmanian species now under description. The Tasmanian 

 shell may be distinguished from K. matthewsi, Iredale, by 

 (1) the slender, tapering lance shape of the ''oar-headed 

 spicules," this feature being constant from the sm.allest up 

 to the largest specimens; and (2) the sculpture is less raised 

 and prominent, the large, rounded, erect pustules of K. 

 matthewsi are, in this species, flattened as if a plane had 

 been passed over them. The general appearance, in spite of 

 its variability, is quite distinct. 



