In _Cypraea_ (Fig. 81) these lobes, or tentaculae, are a prominent feature of the animal, and also in certain genera of the Trochidae (Fig. 82). In most of the carnivorous land Pulmonata--_e.g._ _Testacella_, _Rhytida_, _Ennea_--there are developed, under the lower pair of tentacles, and close to the mouth, large labial palps or feelers. These are connected with the cerebral ganglion by a very large nerve, and may therefore be supposed to be of extreme sensitiveness. In some of the large carnivorous forms (_Glandina_, _Aerope_, compare Fig. 21, p. 54) these palpae are of great size, and curl upwards like an enormous pair of moustaches. When a _Glandina_ seizes its prey, the palpae (see Fig. 83) appear to enfold it and draw it in towards the mouth. [Illustration: FIG. 81.--_Cypraea moneta_ L., showing tentaculae at edge of mantle, which partly envelops the shell: =Si=, siphon; =M=, =M=, mantle; =F=, foot; =T´=, tentaculae at edge of mantle. (After Quoy and Gaimard.) × 3/2. [Illustration: FIG. 82.--_Monodonta canalifera_ Lam., New Ireland, showing mantle lobes. (After Quoy and Gaimard.)] [Illustration: FIG. 83.--_Glandina_ seizing its prey, with buccal papillae turned back. (Strebel.)] It is in the Opisthobranchiata that the organs of touch attain their maximum development. Many of this group are shell-less or possess a small internal shell, and accordingly, in the absence of this special form of defence, a multiplied sense of touch is probably of great service. Thus we find, besides the ordinary cephalic tentacles, clusters or crowns of the same above the head of many Nudibranchiata, with lobe-like prolongations of the integument, and tentacular processes in the neighbourhood of, or surrounding the branchiae (see Figs. 58 and 84), or even projecting from the whole upper surface of the body (Fig. 5, C). In the Pelecypoda, the chief organs of touch are the foot, which is always remarkably sensitive, especially towards its point, the labial palps on each side of the mouth, and the siphons. In certain cases the mantle border is prolonged into a series of threads or filaments. These are particularly noticeable in _Pecten_, _Lepton_, and _Lima_ (Fig. 85), the mantle lobes of the common _L. hians_ of our own coasts being very numerous, and of a bright orange colour. In many genera--_e.g._ _Unio_, _Mactra_--this sensibility to touch appears to be shared by the whole mantle border, although it is not furnished with any special fringing. The ‘arms’ of the Cephalopoda appear to be keenly sensitive to touch, and this is particularly the case with the front or tentacular pair of arms, which seem to be employed in an especial degree for exploration and investigation of strange objects. [Illustration: FIG. 84.--_Idalia Leachii_ A. and H., British seas; _br_, branchiae. (After Alder and Hancock.)]