28 Transactions of the Boyal Society of South Africa. 
convex and of graduating depths which are ornamented with 
numerous equidistant, longitudinally curved plications separated by 
fairly wide interspaces, the entire surface being covered with in- 
numerable spiral and longitudinal striae, thus establishing a minutely 
decussated structure. The apex of the fossil is obtusely pointed, 
whilst the three succeeding whorls are well inflated and of com- 
paratively smooth surface. 
Dimensions. — 
Height 13 mm. 
Diameter 7 ,, 
Being only a fragment, this specimen retains no indication of the 
digitate expansion, nor is there any evidence on the side of the spire 
of the labrum's extension in that direction. It probably belongs to 
Tate's genus Perissoptera, of which Mantell's Bostellaria parkinsoni 
from the Albian of Blackdown, may be regarded as the type, in which 
" the wing is applied against the last whorl but one, and not ex- 
tending on the rest of the spire" (Tate, Geol. Nat. Hist. Bepertory, 
1867, p. 98). 
This genus extends from Neocomian to Danian times (see 
Cossmann, Essais de Paleoconchologie, 1891, part 6, p. 95). 
Although the character of the sculpture of the African shell would 
favour its relationship with such a form as the Albian species 
referred to, much better material is required before a more certain 
determination can be arrived at. 
Locality. — North end of False Bay. 
FaxMily FUSID^. 
Genus SEMIFUSUS, Swainson, emended P. Fischer. 
= Hemifusus, Swainson. 
A Treatise on Malacology, 1840, pp. 91, 308; Manuel de Conchyli- 
ologie, 1884, p. 622. 
Semifusus, sp. 
Plate IX., fig. 6. 
Description. — Specimen consisting of a body-whorl in the dorsal 
position with a wide and gently excavated posterior region, succeeded 
by a pair of sharply developed carinations 4 mm. apart, then 
anteriorly rapidly contracting into a funnel-shaped contour and 
ending with a narrow prolongation. The anterior surface is covered 
by a series of nearly equidistant spiral lines which enclose finer 
spiral striations, the whole being crossed by numerous fine, radio- 
