34 FOSSIL CIRRIPEDIA. 
these peculiar carinze under S. maximum, had not the upper part in one specimen actually 
retained all the usual characters of S. maximum, the precise line where the manner of 
growth had changed, being distinctly visible. It is represented in Plate II, fig. 2, aand 6. 
Amongst the Scanian specimens, some make an approach to this variety. 
ScALPELLUM MAXIMUM, vaR. suLcaTuM. ‘Tab. II, fig. 3. 
PoLLiciPEs sutcatus. J. Sowerby. Min. Conch., pl. 606, solummodo, fig. 2. Fig. 7 
fortasse Carina P. Angelini. Fig. 1, Tergum fortasse P. 
striati.) 
S. carind introrsiim valde arcuatd, sub-carinatd; valve latitudine circd dimidium 
altitudims aequante, tecto transverse prerupté arcuato; parietibus intra-parietibusque 
latiusculis. Apice solide repleto, liberé pauluhim prominente; superficie ewternd striis 
paucis, rotundatis, ad alterum’ vel utrumque latus costarum duarum tectum et parietes 
separantium. 
Carina considerably bowed inwards, subcarmated; width of valve about half of the 
depth; tectum in a tranverse line, steeply arched; parietes and intra-parietes rather 
wide; apex filled up solid, and projecting freely a little; exterior surface with a few 
rounded strize on either one or both sides of the two ridges which separate the tectum and 
parietes. 
Having had the advantage of seeing Mr. J. Sowerby’s original specimen, the valve 
now to be described is certainly that figured by him as Pollicipes sulcatus. As already 
stated, certain specimens of this variety differ strikingly from the carme typical of S. 
maximum ; Whereas others, from the same formation and locality, are so intermediate 
that they can, with difficulty, be arranged on either side: this is also the case with 
one from Cyply bei Mons, in Belgium. This variety is common in the Upper Chalk 
of Norwich. 
In a well-marked specimen of this variety, the chief distinctive characters, as contrasted 
with the true S. maximum, consist in the tectum being more steeply arched, in the depth 
of the valve bemg much greater than the width, in the intra-parietes and parietes being 
more developed, in the whole valve bemg more bowed inwards, in the walls bemg 
thicker and apex filled up solid, in the surface having a few fine raised lines on each 
side of the ridge separating the tectum and parietes, and, lastly, in the tectum being 
sub-carinated. 
1 If I am correct in considering the carina of P. sulcatus to be only a variety of that of S. maximum, 
the tergum figured by Mr. Sowerby as belonging to his P. sulcatus cannot so belong; for it does not at 
all resemble the homologous valve of S. maximum. I believe from the character of the ridge running from 
the apex to the basal angle, that it belonged to a Pollicipes, which must have been coarsely striated longi- 
tudinally, and therefore I have provisionally described it under Pollicipes striatus. 

