T. H. Withers—New Chalk Cirripedes. 153 
basal margin. The type of S. trilineatum (B.M., 38,461) was collected 
by W. Griffiths in the Grey Chalk (Cenomanian) of Dover. 
S. accumulatum also disagrees with S. angustatum (H. B. Geinitz) 
from the Planerkalk of Strehlen, Saxony, and S. guadricarinatum 
(A. Reuss)* from the Planerkalk of Bohemia, in the absence of 
intraparietes. S. quadricarinatum further differs in the abrupt 
truncation of its basal margin. 
2. ScALPELLUM coMPTUM, sp. noy. Fig. 5. 
Diagnosis. —General outline of tergum almost rhomboidal, ornamented 
with fine raised longitudinal ridges, some being finer than others. 
Apex pointed, but not sharply; basal angle probably rounded. Carinal 
margin forming an obtuse angle. Scutal margin sinuous, longer than 
the occludent margin, which is almost straight. A delicate furrow 
divides the valve unequally from the apex to the basal margin, the 
oceludent portion being in its widest part about three times the width 
of the carinal portion. Carinal portion of valve ornamented with 
several fine raised longitudinal ridges, one of which is situated 
immediately at the side of the furrow, making the furrow more con- 
spicuous. Occludent portion almost equally divided by a prominent 
raised ridge, somewhat coarser than the others, extending from the 
Fic. 5. Scalpellum comptum, T. H. Withers, sp. nov. External view of left 
tergum, x 4 nat. size. Aptian, Lower Greensand: Sevenoaks, Kent. 
(B.M., I. 13,403.) . 
apex to the scutal margin. Between this ridge and the furrow the 
valve is ornamented with longitudinal ridges, which are finer and 
less elevated than those on the rest of the valve. The occludent 
margin has a raised border ornamented with several longitudinal 
ridges, similar in size to those on the carinal portion of the valve, 
followed by a wide groove, almost smooth, extending from the apex 
to the scutal margin, which is immediately bounded by the single 
longitudinal ridge. The growth-lines are more conspicuous on the 
occludent portion, where they are sinuous. This sinuosity is more 
marked between the single longitudinal ridge and the occludent 
margin. 
1 Die Versteinerungen von Kieslingswalda, ete., Dresden and Leipzig, 1843, p. 7, 
pl. iv, fig. 10. 
> Die Versteinerungen der Bohmischen Kreideformation, Stuttgart, 1846, p. 105, 
pl. xlu, fig. 18. 
