Page:The common shells of the sea-shore (IA commonshellsofse00wood 0).pdf/41

Rh top of each valve. At fig. 6 this shelly plate or "ossicle" is shown as it appears in its place, and a magnified figure of it is also given. It is exceedingly convex on one side and flattish on the other, but with a deepish hole in it. It is a small species, the specimen being represented of the natural size.

At fig. 9 of the same illustration is seen a shell belonging to the same group, and which we may call, for a reason which will presently be seen, the. Its scientific name is Cochlodesma prætennue.

This is a delicate and fragile shell, small, being seldom an inch in length, at all events on English shores, though off the Scottish coast it sometimes measures an inch and a half in length. When recent, the shell is covered with a very fine membrane; but when dry, the membrane shrinks closely to the shell, and finally flakes off, leaving the china-white shell exposed.

The chief peculiarity of the shell lies in the hinge. If the reader will again refer to the illustration, he will see that from the hinge of the upper valve a small shelly plate projects into the interior. This plate is exactly like the bowl of a spoon, and affords the reason for the name of Spoon-basket. Corresponding to the "spoon," a stout piece of elastic cartilage is attached to the other valve, serving, as has already been mentioned, to hold them apart.

Our next group of shells is that curious family which are appropriately termed Razor-shells, because, when perfect, the shell looks something like the handle of a closed razor. To mistake a Razor-shell is impossible, as there is no other group that bears any resemblance to these curious molluscs. Yet a short inspection of the shell will show the connection that exists between them and the species which have already been described. If it were possible to soften a Basket or a Lantern-shell, and draw it out lengthwise, as a glass tube can be drawn out in a spirit-lamp, a very