UNRECORDED GENERA OF THE OLDER TERTIARY FAUNA, 193 
species of the genus ; A. conica, Hutton, of the Oamuru formation 
(= Eocene) in New Zealand, is a Monostychia. 
Genus Laganum. 
I avail myself of this opportunity to make diagnostically known 
a species which belongs to our Older Tertiary ; the genus is 
essentially of recent date, as only one fossil species LZ. multiforme, 
Martin, is recorded, which belongs to an unknown horizon of the 
Javanese Tertiary. 
LAGANUM -PLATYMODES, spec. nov., Pl. xiii., fig. 4. 
Outline of test subquinquangulated, varying from nearly circular 
to broadly elliptic, rarely moderately narrow-oval ; margin not 
inflated or very slightly so; upper surface flat or a little elevated 
apically; petals elongate, extending three-fifths of the distance to 
the ambitus, lanceolate, closed; genital pores four; periproct cir- 
cular, situated at about two-fifths the distance between the margin 
and the peristome from the margin. Dimensions of a specimen of 
average size and shape :—length 34, breadth 31, height 6 mm. 
Localities:—Miocene: Hallett’s Cove and Aldinga Cliffs, east 
side of St. Vincent Gulf, South Australia (common). 
The form of this species varies from that of Z. Bonani, Klein, 
to L. ellipticum, Ag., but it has not the tumid margin of those 
species ; from the first it further differs, as also from LZ. depressum 
and L. multiforme, Martin, in its closed petals, four genital pores 
and submarginal periproct, and from the latter in its closed petals 
and four genital pores. 
Genus Sismondia. 
SismonDIA Murravica, spec. nov., Pl. xiii, fig. 5. 
Outline subdecagonal, broadly elliptical, being a little longer 
than wide, width greatest in front of apex coinciding with a plane 
through the ends of the antero-lateral ambulacra; actinal and 
abactinal surfaces flat with a high abruptly-rounded margin ; 
apical disc subcentral, posterior, forming a slightly raised boss ; 
genital pores four ; petals elliptic, the width about two-thirds the 
length, not closed, extending for about two-thirds of the radius 
M—Suly 5, 1903, 
