218 
Diagnosis.—From Nacella crebristriata, Verco; it is less 
solid, more rounded, has its apex less excentric, and fewer 
and less valid ribs. From Scutellina calva, it is narrowed 
anteriorly, has no crowded axial lirz, is white-ribbed. From 
Cocculina tasmanica, Tate and May, its apex is more central 
and leans backwards. 
Obs.—In some examples the opaque radii are much nar- 
rower, or a wide and a narrow one may alternate. The opaque 
lines are not continuous, but composed of arrowheads, with : 
their points towards the margin, or of zig-zags, or dots. AW 
Its generic location is somewhat dubious. 
Family TROCHID Ai. 
Genus Basiutssa, Watson. 
Basilissa-radialis, Tate; var. bilix, Hedley, sp. {22 
rag 
, ypolilir Blbsc, toss 253) 
Seguenzia Agel E Tate, Trans. Roy. Soc., S.A., xiii. ; 1890, 
p. 192, pl. ix., f. 
‘Astele bilix, Hedley, Records Austr. Mus., vi., pt. 2, 1905, 
p. 48, f. 13. \ 
Shell depressedly conical, of seven and a quarter whorls, 
including a homostrophe smooth protoconch of one and a 
quarter whorls. 
Spire somewhat gradate. In the first whorl one marked 
spiral rib; in the rest two becoming gradually more valid and 
distant. In the third whorl a secondary threadlet between 
these; in the fourth a _ threadlet between the first 
spiral and the upper suture; in the fifth two terti- 
aries, one between each spiral and the secondary threadlet. 
In the sixth, or body-whorl, another spiral rib appears below © 
, and nearly equal to the lower of the two spirals; it forms the 
periphery and the suture, and, separated from its fellow by a 
furrow, gives an apparent canaliculate suture. The base is 
flatly rounded with eight equi-distant, nearly eaual, concen- 
tric rounded spiral lire, as wide as their interspaces. The 
surface is cancellated by crowded narrow erect lamellz, cross- 
ing the spirals and sinuous, but not following exactly 
the outline of the labrum, and ending at the outer 
basal _ lira. Crowded radial striz cancellate and 
granulate the base, and extend to the lira nearest the umbil- 
icus. Aperture obliquely quadrate, with a large posterior 
2: sinus in the outer lip, rather deeper than wide; a second 
at the baso-labral junction, beginning at the third spiral rib, 
about as deep as the infra-sutural one, and rather wider : and 
_a third shallow and wide at the baso- columellar angle. Colu- 
mella oblique, concave, expanded towards the umbilicus, trun- 
