68 FOSSIL CIRRIPEDIA. 



on the lower latera, — this species comes much nearer to P. mitella than to any other recent 

 species ; I beheve, however, that it must have had much fewer valves, i From the growth 



' 13. PoLLiciPES VALiDUs, Tab. IV, fig. 2. 



PoLLiciPEs VALIDUS. Steenstrup. Kroyer's Tidsskrift, 1839, pi. v, figs. 28 — 32. 



P. scutis crassissimis, angustis ; margine occludente externb costd rotundatd forti firmato ; intus promt- 

 nentid rostrali infra marginem rectum basalem dependente ; costd ab apice ad marginem hasalem propius 

 ad rostralem quam ad basi-lateralem angulum accedente. Carind lavissitnd, transverse semicylindricd ; parte 

 superiori liber e prominente, intern^ aut pland aut cristd centrali instructd. 



Scuta, extraordinarily thick, narrow ; occludent margin exteriorly strengthened by a rounded, strong 

 ridge ; internally, at the rostral angle, a blunt tooth depends beneath the straight basal margin : the ridge 

 running from the apex to the basal margin is nearer to the rostral than to the baso-lateral angle. Carina 

 very smooth, transversely semi-cylindrical ; upper freely projecting portion internally, either solid and flat, 

 or vfith a central prominent crest. 



Scania, Sweden. Mus. Univers. Copenhagen. Petersberg, near Maestricht. 



My materials consist of several scuta and carinee, sent me by Professor Steenstrup as belonging to the 

 same soecies, which is likewise the opinion of that able collector, M. Angelin, who has found this species in 

 various localities in Scania. A very fine carina, from near Maestricht, has been sent to me by Krantz, of Bonn. 



Valves, remarkably thick, massive, and strong. Scuta (fig. 2, e,/, g, nat. size) elongated, being twice 

 as long as broad ; slightly convex ; whole upper part bent towards the terga ; surface, in some specimens, 

 with traces of longitudinal striae. Basal margin foi'med obscurely (partly owing to the rubbed condition of 

 aU the specimens), by two lines meeting each other at a very open angle. Occludent margin much arched, 

 forming with the basal margin, taken as a whole, an angle of about 60° : tergo-lateral margin nearly straight, 

 forming a rectangle with the adjoining portion of the basal margin. That part of the valve formed by the 

 upturned zones of growth is narrow, being, in the widest part, barely half the width of the other part of the 

 valve. The occludent margin is strengthened by a rounded, strong, projecting ledge, running along its entire 

 length ; the basal end of this ledge, and consequently the lines of growth crossing it, are oblique, and 

 sUghtly upturned. A slight ridge, or angle, runs from the apex to the baso-lateral angle, and a second, still 

 shghter ridge, to a point in the basal margin rather nearer to the rostral than to the baso-lateral angle. 

 Close to the rostral angle, the internal lamina of the shell is produced downwards into a strong, blunt tooth, 

 which (when not too much worn) can be seen from the external side, depending beneath the basal margin : 

 this is the most singular character of the species. The internal occludent edge is broad (and of nearly 

 the same breadth throughout the whole upper part of the valve), flat, and marked by lines of growth : this 

 striated internal edge is separated from the smooth, depending, rostral tooth, by a very oblique line. The 

 pit for the adductor muscle is very deep : above this pit there does not appear to have been any furrow on 

 either margin, or any marked central prominence. 



Carina (fig. 2, a, b, c, d, nat. size), broad, extremely solid, much bowed inwards ; the upper part, even 

 more than half the valve in length, must have freely projected ; exterior surface transversely semi-cylindrical, 

 or rather steeper than a semi-cylinder, but not at all carinated : basal margin not at all protuberant ; lateral 

 angles, or heels, just perceptibly projecting below the central part of the basal margin : in the Maestricht 

 specimen it appears that there was a very slight furrow near each exterior lateral margin, making them just 

 perceptibly protuberant. The internal, smooth, corium-covered surface is concave, forming almost an equi- 

 lateral triangle (b) : above this, the inner freely projecting portion is either filled up flat, or forms a central 

 prominent crest (d). 



Affinities. We shall immediately see that this species appears to be most closely allied to P. gracilis, 

 of Roemer : it is also allied to P. dorsatus, by the strength of the valves, by the occludent margin of the 



