406 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [ Mar. 23; 
faint lines of growth; aperture oval; subtruncated in front; outer 
lip thin; columella without a fold. 
Length 0-27 inch ; last whorl about 55, the length of the shell. 
Locality y. Yellow Lias (zone of Am. ibew) Hewletts, Cheltenham. 
CeRitHium SLATTERI, noy.sp. (PI. XXVI. fig. 7.) 
Shell elongated, turreted, acute; whorls ten, subquadrate, separated 
by a broad and deep suture; ornamented by about twenty-five 
obliquely transverse ribs, which, where crossed by the four equidistant 
longitudinal costs, are raised into large closely set nodulations ; 
aperture orbicular; columella straight, outer lip slightly effuse. 
The longitudinal ribs are sometimes three in number, and not 
unfrequently with a smaller intermediate rib. 
Length 0:25 inch. 
Locality. Zone of Am.Jamesoni: Aston (7'.S.), Cheltenham (2. 7.). 
The species is dedicated to T. Slatter, Esq., whose collection of 
fossils from Aston Magna has materially increased the value of the 
present communication. 
LIMA SCABRICULA, nov. sp. (Pl. XXVI. fig. 15.) 
Shell convex, oblong-ovate, ornamented with about twelve large 
acute coste, which are finely ‘and closely transversely striated, and 
towards the front carry nodes; the sulci are occupied by three 
slender costelle, the outer ones of which are crenately dentate ; the 
median costella is lamelliform; hinge-line straight, beaks acute 
and distant; hinge-area narrow, elongated; ligamental pit circular, 
external ; ears short with radiating nodulose ribs. 
Dimensions. Length 0-515 inch; breadth 0-4 inch; thickness 
0°35 inch ; length of hinge-line 0-22 inch. 
Affinities. L. scabricula has much the figure of some varieties of 
Timea acuticosta, Lima hettangensis, L. pectinoides, &c., but differs 
from all in combining the characteristic ornamentation of several of 
the duplicate Zim, none of which, however, present the interme- 
diate ribs as in this species. 
Locality. Zone of Ammonites Jamesoni: Aston Magna (Slatter) § 
Middle Lias (Am. margaritatus), Kontaine-étoupe-four, Caen (Tes- 
son, Coll. Brit. Mus.) 
ARCA NUMISMALIS, nov. sp. (PI. XXVI. fig. 3.) 
Shell small, oblong, inflated, inequilateral; anterior side short, 
subtruncate, posterior obliquely truncate; umbones large, sub- 
approximate, incurved and directed forwards, medially impressed ; 
surface with undulate concentric ribs, which are subacute and 
minutely granulated ; apical portion of left valve with radiating 
costellee, of the right with fine striations. 
Dimensions. Leng th 0°315 inch ; height 0:25 inch; diameter 0-2 
inch; length of anterior side 0: 133 in. 
Locality. Zone of Ammonites Jamesont, Aston Magna (Slatter). 
ANATINA NUMISMALIS, noy. sp. (Pl. XXVI. fig. 13.) 
Shell small, elliptic-elongate, subequilateral, and somewhat com= 
