158 
Transactions of the Society. 
Frondicularia planifolium (plate IV. fig. 1 a, b). 
Shell ovate, pointed at the ends, the outline undulated ; very thin, 
and with surfaces quite flat ; the primordial chamber small, sub-oval, 
and with a central costa; chambers numerous, often as many as 
thirteen. The surface of the shell sometimes faintly striate. Length 
1/18 in. 
This elegant species can be distinguished from the nearly allied 
F. Guestphalica by its thinness and its possessing a smaller and more 
spherically shaped initial chamber. 
F. planifolium is found at Folkestone in zone vi., very rare ; zone 
vii., rare ; zone x., rare. 
Frondicularia Guestphalica Reuss (plate IY. fig. 2). 
Frondicularia Guestphalica Reuss, 1860, Sitzungsb. d. k. Ak. 
Wiss. Wien, vol. xl. p. 195, plate vi. fig. 2. 
The specimens which were described by Reuss were obtained from 
the Minimus- clay of Westphalia. The initial chamber of this species 
is usually more lanceolate than that of the other species of Gault 
Frondicularise. It is found at Folkestone in zone xi., 20 ft. from the 
top, frequent; 12 ft., very rare. 
Frondicularia microdiscus Reuss (plate IV. fig. 3). 
Frondicularia microdisca Reuss, 1860, Situngsb. d. k. Ak. Wiss. 
Wien, vol. xl. p. 195, plate v. fig. 4. 
This species was described from the Cretaceous detrital sand of 
Hamm in Westphalia, and from the Gault of Folkestone (Reuss). 
One of the Gault specimens in my collection is feebly costulate. 
This species is found at Folkestone in zone x., rare ; zone xi., 20 ft. 
from the top, very rare. 
Frondicularia quadrata (plate IY. fig. 4). 
Shell trapezoidal in outline, consisting of six chambers with 
obscurely-marked sutures; the nuclear chamber small, circular, 
slightly inflated, and surrounded by a carinate border ; the edge of 
the shell square. The surface of the test traversed by about eight 
broken undulating costae. Length 1 /20 in. 
This conspicuous form is represented by one specimen only, from 
the Gault, in zone x. 
Frondicularia perovata (plate IV. fig. 5 a, b). 
Shell of sub-oval form, pointed at the extremities, the edge grooved. 
Chambers from four to eight in number ; the nuclear chamber inflated, 
but small ; the others with convex surfaces. The limbs of the last 
two chambers embracing three-fourths of the length of the shell. 
Surface of the test sometimes faintly striate. Length 1/16 in., 
breadth 1/24 in. 
