138 
its attached border. The single lateral is stout and rather 
short, and has one obliquely placed cusp without serrations. 
The marginals are trapezoidal flat plates, thickened along 
their inner end, and the whole or larger part of their upper 
margin. Mr. Kesteven, in executing the drawings, detected 
a small accessory plate of chitin (fig. 147). It is somewhat 
pyriform, stouter at its narrow, attached end, and thinner and 
slightly striate at its free, expanded extremity. Its height 1з 
about one-half that of the rachidian tooth, outside of which 
it stands, with its base about half-way between this and the 
lateral. As the laterals overlap the outer fourth or third of 
the rachidian, this plate iies behind or between the laterals, 
and being comparatively thin it cannot be seen through the 
much denser laterals; but in a dismembered radula it can be 
certainly recognised. 
Cadulus acuminatus, Tate. 
This shell is first referred to as a South Australian species 
by G. F. Angas, in a paper entitled “A List of Additional 
Species of Marine Mollusca . . . of South Australia,” in 
Proc. Zool. Soc. of November 5, 1878, p. 868, species 44, 
Cadulus acuminatus (7) Desh., М.В. in coll., Cuming; Hold- 
fast and Aldinga Bays (Tate) ; also Port Jackson. In the Trans. 
and Proc. Roy. Soc. of South Australia, vol. ix., p. 194, 
1887, Tate, in a paper of October 5, 1886, on "The Scapho- 
pods of the Older Tertiary of Australia," includes Cadulus 
acuminatus, of which he gives a short description, cites 16 
from the “oyster beds of the Upper Aldinga series," and 
says, “the species is not uncommon 1n shell sand on the shores 
of St. Vincent Gulf.” Іп the Manual of Conchology, vol. 
xvii, p. 183, Pilsbry gives C. acumwnatus, Tate, pl. xxxii, 
figs. 47, 48, 49, with a full description. 
I have dredged it in St. Vincent and Spencer Gulfs and 
Investigator Straits and Backstairs Passage at five fathoms, 
(14 dead), at nine fathoms (29 dead and 3 alive), at seven- 
teen fathoms (80 dead and 12 alive and 7 initial tubes), be- 
sides 35 dead and 5 alive at unrecorded depths. These living 
examples enable me to make some additions to and altera- 
tions in Pilsbry's description of what were doubtless beach- 
rolled specimens. Though glossy and smooth to the naked 
eye, under the microscope very fine, crowded transverse 
scratchings are visible. Though usually quite clear and 
glassy, but for the white opaque internal callous ring near 
the posterior end, many individuals have fine, milky, trans- 
verse lines, and some have opaque, white, subdistant, inter- 
rupted bands, or on one side a group of round or oval white 
blotches. 
