
156 
Rapid Bay (Angas), Holdfast Bay (Bednall), and New South 
Wales (Cox, Brazier). J have specimens dredged by Dr. 
Verco in Backstairs Passage, and either good specimens or 
valves from Cape Jervis, Normanville, Aldinga, and Brighton. 
The splashes of pink colouring are very vivid when preserved 
in spirits. The peculiarly large and broad anterior valve 
easily differentiates this species from L. volvox. It flattens 
itself so closely to the rocks and is so covered with foreign 
growth that I have had the greatest difficulty in detecting one 
on a rock which I had been examining for some minutes. 
m. MOPALIJD Ai, Pilsbry. 
38. OnE ETE ida, Blainville, 1825. TbALS 
Chiton albidus, Blainville, Dict. Sci. Nat., 1825, vol. xxxyi4 
p. 547; Pilsbry, Man. Conch., 1893, vol. xv., p. 105. 
C. glaucus, Quoy and Gaimard, Voy. ‘‘Astrolabe,’’? Zool., 
1834, vol. iii., p. 376. 
(?)C. petholatus, Sowerby, Mag. Nat. Hist., new series, iv., 
p. ae May, 1840; Conch. Illustr., f. 64, 65, and var. porphyrius, 
f, 59! 
Chetopleura conspersa, Adams and Angas, P.Z.S., 1864, 
p. 198; P.Z.S., 1865, p. 187. 
Plaxiphora albida, Blainville: Thiele, Zool. Chun, 1909, Heft 
lvi., p. 24, pl. iii, figs. 22, 23. 
P. tasmanica, Blainville: Thiele, loc. cit., p. 25, pl. ilii., 
figs. 24-26. 
P. bednalli, Blainville: Thiele, loc. cit., p. 25, pl. iii., 
figs. 27-30. 
P. petholata, Sowerby: Pilsbry, Man. Conch., vol. xiv., p. 
323; Bednall, Proc. Mal. Soc., London, vol. ii., part 4, April, 
1897, p. 154, 
P. albida, Blainyille: Iredale, Proc. Nat. Soc., London, vol. 
ix., part 2, June, 1910, p. 98. 
South Australian chiton-hunters will always be grateful 
to Mr. Iredale for his elaborate paper on the Plaziphoras, 
and to Dr. Thiele for his “Revision des Systems der Chitonen.” 
But we part with the old name of petholata with regret. 
Sowerby’s description of petholata, loc. cit., is a complete 
account of our albida, while Blainville’s description of albida 
in Pilsbry, Joc. cit., is very poor, and might be that of any 
of our Plaxiphora. Is not there a danger in making the 
posterior valve the basis of decision? I have several hundred 
specimens of Plaxiphora before me from all parts of Aus- 
tralia, most of them collected by myself, and the tail valves 
differ so much in the same species according to size and growth 
that I agree with Iredale that Dr. Thiele, “through lack of 
specimens, has laid too much stress upon the value of the 
shape of the valves.” The three South Australian Plaai- 
PE SAAE wz! 

