157 
phora are easily separated. The zigzag markings of albida 
(? petholata), the smooth reticulated markings of costata 
(¢ glauca), and the strongly raised nodules of the lateral area 
in matthewsi (? conspersa) make the separation easy except 
in worn specimens. 
Mr. Gatliffe, of Victoria, has taken considerable pains 
in identifying: the Plaziphora, and agrees with Dr. Thiele in 
identifying our P. glauca with P. albida, Blainville. 
P. albida is often found at and above high-water mark, 
and generally adheres to one spot without moving about like 
other chitons. At Robe I have seen hundreds alive, blistering 
in the sun. I have collected it all around the coast of South 
Australia, from Port MacDonnell to Streaky Bay, as well as 
Queensland, Victoria, and Tasmania. Going out from Streaky 
Bay 40 miles to St. Francis Island, P. costata takes the place 
of albida, and that would seem to continue right on to Wes- 
tern Australia, for I obtained costata at Albany, Bunbury, 
Rottnest Island, and saw nothing of albida. 
I don’t know if pearls are often found in chitons, but 
I extracted a blue egg-shaped pearly substance from the 
interior Bg a Plaxiphora albida. 
39. Koinwp laze, | 06 reddle, 1910. 
Plaxiphora conspersa, non Adams and Angas: Bednall, 
Proc. Mal. Soc., London, 1897, vol. ii., p. 154. 
P. matthews, Tredale, Proc. Mal. Soc., London, vol. ix., part 
ii., June, 1910, p. 99. ; 
This is the rarest of South Australian Plaxiphora. It 
is found in deeper water than either albida or costata. Its 
great breadth in proportion to its length easily distinguishes 
it from either of these. I have specimens from Marino, Trou- 
bridge, Second Valley, and St. Francis Island. I have also 
collected it on the north-west coast of Tasmania. Iredale’s 
description, Joc. cit., is very good, but the absence of plates 
is a hindrance to identification. 
The description of Chetopleura conspersa, Adams and 
Angas, P.Z.S., 1864, p. 193; Angas, P.Z.S., 1865, p. 187, 
agrees so well with matthews: that I place it under a new 
nomenclature with considerable diffidence. 
- A very pretty half-grown specimen was taken by Mr. F. 
LL. Saunders at Port Noarlunga. The nodules on the lateral 
“areas are like teay-drops. 
O- e ens 
Wwe Ar -- costata, Blainville. 
Chiton costatus, Blainville, Dict, Sc. Nat., xxxvi., p. 548; 
Pilsbry, Man. Conch., vol. xv., p. 105. 
C. glaucus, Quoy and Gaimard, Voy. ‘‘Astrolabe,”’ Zool., iii., 
376. 

