30 FOSSIL CIRRIPEDIA. 



is in Mr. Bowerbank's collection from the Lower Chalk of Maidstone. These valves are 

 marked with longitudinal raised striae more plainly than is the carina. 



Carina (fig. 12); moderately bowed inwards; inner margin nearly straight; widening 

 very gradually downwards from the apex, of which a very small part is filled up solid, 

 and must have ])rojected freely ; walls rather thin. Both tecta and parietes are regularly 

 striated longitudinally, with raised, hair-like, fine lines scarcely visible to the naked eye ; 

 one central, and two or three on each side between the tectum and parietes, being about 

 wice as large as the others, and visible to the naked eye. Tecta rather steeply inclined 

 towards each other ; central line sub-carinated ; basal margin rectangularly pointed ; 

 parietes slightly concave, about as wide as half the tectum ; steeply inclined outwards ; 

 separated from the intra-parietes on each side by a slight ridge. Intra-parietes set a little 

 inwards, wider in the widest part than the adjoining parietes or tecta ; extending baseward 

 not as far as the basal margin of the parietes. Depth of valve measured from central crest 

 to either inner edge, nearly equal to the entire width, as measured across from inner edge 

 to edge. In many respects this carina is intermediate between those described under S. 

 maximum and S. maximum, var. sulcatum ; but comes nearest to the latter : the intra- 

 parietes not extending so far baseward ; and the delicately lineated exterior surface gives 

 it, however, a somewhat different aspect. 



Scutum (fig. 11); this valve, from the Lower Chalk of Sussex, resembles that of 8. arcu- 

 atum ; its surface is covered vdth raised strise, which are further apart, and less plain than 

 in the typical specimens of S. arcuatum from the Gault, but resemble those in the variety 

 from the Grey Chalk of Dover. Outline trapezoidal : the baso-lateral angle is very broad, 

 rounded, and protuberant ; no ridge runs from it to the apex : the basal margin projects 

 very slightly close to the rostral angle, and the tergal margin is not inflected as in S. 

 arcuatum. The internal surface of the valve, along the tergal margin, is not furrowed or 

 marked by lines of growth : I have no doubt that this valve is, at least, distinct from 

 S. arcuatum. 



Tergum. This valve, from the Lower Chalk of Maidstone, resembles that of 8. arcuatum, 

 var. from the Grey Chalk ; it is, however, slightly more elongated : it further closely 

 resembles a tergum, which I have provisionally attributed to Pollicipes striatus, differing 

 from it in being less elongated, and more especially in the absence of a ridge, steep on the 

 carinal side, which in that species runs from the apex to the basal angle. 



Finally, I may remark, that these three valves, on the supposition that they have been 

 rightly attributed to one species, indicate a form intermediate between Scalpellum maximum 

 of the Upper Chalk, and S. arcuatum of the Grey Chalk and Gault. 



