152 T. H. Withers—New Chalk Cirripedes. 
Darwin's theory of evolution to the fossils which his study has 
rendered. classical. . | 
1. ScALPELLUM ACCUMULATUM, sp. nov. Figs. 1-4. 
_ Diagnosis.—Carina narrow, moderately tapering, considerably bowed 
inwards, with inner margin much curved, not divided into parietes and 
intraparietes; apex pointed; basal margin rounded. Tectum very 
gently convex, almost flat, with obscure central ridge, marked off from 
the parietes by a well-developed ridge. Parietes narrow, less than 
half the width of the tectum, inflected, gently concave. Ornament: 
fine obtusely-angled V-shaped growth-lines continued over the parietes ; 
near the basal margin are five ridges, similar in shape to the growth- 
lines, but irregularly spaced, strongly marked, and sharper on the 
parietes. 
Fic. 1. Scalpellum accumulatum, T. H. Withers, sp. nov. External view of carina, 
x 2 nat. size. Aptian, upper part of Lower Greensand (Folkestone 
Beds) : Folkestone, Kent. (B.M., I. 12,928.) 
Id. Side view, x 2 nat. size. 
Id. ‘Transverse section at one-third from apex, x 2 nat. size. 
. Id. Transverse section at one-third from base, x 2 nat. size. 
Holotype.—A carina (B.M., I. 12,928) collected by Mr. F. H. Butler. 
The specimen, of which the basal margin is slightly broken, is in 
a matrix of very coarse-grained greensand. Extreme length 17mm., 
breadth 4mm. 
Horizon and Locality.—Aptian, upper part of Lower Greensand 
(Folkestone Beds): Folkestone, Kent. 
Comparison with other Species.—Scalpellum simplex, Darwin (1851, 
p- 39, pl. i, fig. 9), of which only a single carina is known, is the only 
species of the genus previously known from the Lower Greensand 
of the British Isles. It differs from S. accumulatum in having the 
parietes more inflected, set inwards, and not extending to the basal 
margin. Also in the much more convex transverse section of the 
carina, and the smooth surface. S. accumulatum may also be compared 
with S. arcuatum, Darwin (1851, p. 40, pl. i, fig. 7), from the Gault, 
and S. trilineatum, Darwin (1851, p. 38, pl. i, fig. 5), from the Grey 
Chalk, with both of which it agrees in the absence of a division 
into parietes and intraparietes. From S. arcuatum it is readily 
distinguished by the absence of the longitudinal ridges, and from 
S. trilineatum by the absence of the well-marked rounded central 
ridge, and the presence of the prominent V-shaped ridges near the 
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