224 
Aedialble : i 
JV OTrigonia margaritacea, Lamarck, var. bednalli, var. nos. FY 
Pl. xxviii. figs. 1, 2, 3. y/ 
Trigonia margaritacea, Lamarek, Ann. du Mus., vol. iv., p 
355, pl. Ixvii., fig. 2. _ 7. pectinata, Lamarck, Anim. S. Vert., 
1819, vol. vi., p. 63: Eneyc. Meth., 1832, vol. iii., p. 1048. 
The shell here referred to was first taken on the South 
Australian shore, between Glenelg and the Semaphore, by 
Mr. W..T. Bednall, about the year 1865, and was catalogued 
by him in a list of South Australian shells, published (for 
‘private circulation only) in 1875, and was noticed in his ex- 
cellent paper on “Australian Trigonias and their Distribu- 
tion,” in Trans. Roy. Soc. 8. Austr., vol. i., 1878, p. 79, under 
the name of 7’. margaritacea, Lamarck. He said : —“Its par- 
ticular habitats in our waters have not yet been discovered, 
no live specimens having yet been dredged.” In vol. ix., pp. 
101-102, Tate recorded it as having been “dredged in life 
from 8 fathoms in Encounter Bay (R. H. Pulleine).” A few 
years later, when I had the pleasure of Mr. Bednall’s com- 
pany on one of my earlier dredging excursions. we discovered 
it in St. Vincent Gulf, and obtained about 70 specimens, liv- 
ing and dead, from 15 to 20 fathoms, in Yankalilla Bay, 
Dredging since then has revealed a considerable range, both 
in depth and area, as shown by the following details: —It 
has been taken alive at 10 fathoms, 2 small examples; 12 
fathoms, 7; 14 fathoms, 3; 15 fathoms, 3; 17 fathoms, 15; 
19 fathoms, 16; 15 to 20 fathoms, about 50; 22 fathoms, 
18. They have been taken as valves from 9 up to 200 fathoms. 
They have extended from Wallaroo Bay, at 15 fathoms, 
throughout Spencer Gulf, through Investigator Strait, in St. 
Vincent Gulf, as far up as Yankalilla Bay, and through Back- 
stairs Passage. Beyond this, as far as Beachport, where I 
have only tested at depths from 49 to 300 fathoms, none 
but dead specimens have been obtained; though 1 example, 
the largest in my cabinet, perfect, and quite recent, and 
of a white colour, was brought up from 110 fathoms at this 
most easterly of my stations. Their zone is manifestly from 
12 to 23 fathoms, only stragglers occurring at less depths, and 
dead shells at greater depths. 
They are very varied in colour, white, pale yellow, light 
orange, delicate mauve, pink, “erushed strawberry.’ and 
purple. 
This variety is characterized by its very compressed 
shape, its narrow ribs, its large, oblong, plate-like spines, 
broader at their free than at their attached ends, features 
which are exceedingly constant in the very large series ob- 
tained. 7. lamarckii, var. reticulata, Ten. Woods, found off 
the coast of New South Wales, is regarded by Mr. Hedley 
