34 ■ FOSSIL CIRRIPEDIA. 



these peculiar carinac 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, a and b. 

 Amongst the Scanian specimens, some make an approach to this variety. 



SCALPELLUM MAXIMUM, VAR. SULCATUM. Tab. II, fig. 3. 



PoLLiciPES SULCATUS. J. Sowerby. Min. Conch., pi. 606, solumraodo, fig. 2. Fig. 7 

 fortasse Carina P. Angelini. Fig. 1, Tergum fortasse P. 

 striatic 



S. carina introrstm valde arcuatd, suh-carinatd ; valvcB latitudine circd dimidium 

 altitudinis aquarite, tecto transverse jprcerupte arcuato ; parietibus intra-parietibusque 

 latiusculis. Apice solide replefo, libere paululmi prominente ; superjicie externa striis 

 paucis, rotundatis, ad alterum vel utrmnque latus costarmn duarum tectum et parietes 

 separantium. 



Carina considerably bowed inwards, subcarinated ; 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 striae 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 FolUcipes sulcatus. As already 

 stated, certain specimens of this variety differ strikingly from the carinae typical of S. 

 maximum ; whereas others, from the same formation and locality, arc 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 being much greater than the width, in the intra-parietes and parietes being 

 more developed, in the whole valve being more bowed inwards, in the walls being 

 thicker and apex filled up sohd, 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. 



' 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 Pollicipcs, M'hieh must have been coarsely striated longi- 

 tudinally, and therefore I have provisionally described it under Pollicipes striatus. 



