[43]

Through the kindness of Mr Harris, I have examined several valves, which I believe to belong to the same species: the specimens were found in the chalk detritus, and, therefore, may have come from the upper or lower chalk or chalk-marl; but more probably from the upper chalk. With respect to the scuta and terga I have scarcely any doubt, from certain peculiarities, that they belonged to the same species; but with regard to the most important valve, the carina, I cannot feel quite so certain: when the latter is so held, that the parietes are not visible, it has a very close general resemblance to the same valve in Pollicipes rigidus. In the carina, the present species comes closer to S. arcuatum than to any other species; in the other valves, especially in the singular scuta, it departs widely from that and all other known fossil forms, with the exception of S. (?) cretae, of Denmark. All the specimens which I have seen are small; the carina being 0*2 long, and the terga less than 0*15 of an inch in length, in the largest specimens. /

The valves all have their surfaces plainly ribbed longitudinally; the ribs are narrow, and as they cross each zone of periodical growth they are tuberculated.