href="@public@vhost@g@gutenberg@html@files@43305@[email protected]#plate5" class="pginternal" tag="{http://www.w3.org/1999/xhtml}a">Plate V.

Fig. 1-3 also represent genera of Cyprinidæ. They have no bend in the palleal impression. Cardium, or "Cockle," 4-13, presents a peculiarity in the foot, which is large and bent, and enables the animal to leap in a very lively manner. The family of Lucinidæ occupy the remaining figures. Lucina has a curious tongue-shaped doubling of the pallial impression.

Plate VI.

The Kelliadæ, 1-15, are marine, while the Cycladidæ, completing the Plate, are fresh-water bivalves, and may be found in many ponds and rivers.

Plate VII.

Of the Unionidæ, or "Fresh-water Mussels," Unio, 1-3, has teeth on the hinge, and Anodon, 4, has not: it is a thin shell. The foot of these molluscs is very large, and is used in cutting the animal's way through the mud in which it burrows. Of the marine, or true Mussels, Modiola, 6-9, and Crenella, 12-17, have a portion of the shell reaching beyond the point or apex, which in Mytilus is terminal, 18-21. Dreissina, 5, is shaped like Mytilus, but lives in fresh-water docks. The Mytilidæ attach themselves by means of horny threads spun from the foot, and called a "byssus."

Plate VIII.

Shells of Arcadæ, 1-14, have the hinge characterized by a series of teeth on each side of the apex. Nucula, Arca, and Pectunculus are easily distinguished. Limopsis, 14, has a spring pit between the two rows. Our figure of Pinna, 16, is from a young specimen: it grows to great size, and spins a very silky byssus. The shell of Anomia, 18, is fixed to rocks, etc., by means of a bony button passing through a hole or sinus in the lower valve. Lima, 22-24, has a light, thin shell, and its mantle is adorned with beautiful fringes. It swims rapidly through the water by the opening and shutting of its valves, and also has the habit, in seasons of rest, of protecting itself by a network or vest of marine fragments strung together by its byssal threads.

Plate IX.

Contains the shells of our Pectens, or Scallops, 1-16. The animals swim like Lima, as above, and also spin a byssus.

The class Brachiopoda, 17-24, so named because what seem to be organs of locomotion consist of a pair of coiled, ciliated arms, ends the list of Headless Molluscs and their bivalve shells.

Plate X.

Class Pteropoda, 1-4, contains minute Mollusca, with glassy shells variously formed, and wing-like expansions for swimming.

Chiton, 5-17, or "Coat of Mail," which may often be seen incrusting rocks, commences the Gasteropoda; although seemingly fixed, they are capable of locomotion, using the whole of the oval disc, which may be seen on turning them over, for the purpose. The same may be said of the "Limpet" tribe, Patella, 1-22.

Plate XI.

This Plate commences with other forms of the Limpet tribe, Fissurella, 1, 2, with a hole at the top; Puncturella, 3, with a fissure near the top; and Emarginula, 4-6, with a slit at the margin. Haliotis, 7, or pearly "Ear-shell," leads to the Trochidæ, or "Tops," 8-27.

Plate XII.

Ianthina, 1-4, is genus of oceanic molluscs, which are provided with a beautiful floating apparatus, on which the female carries her egg-bags.

Neritina, 5, and the Paludinidæ, 8-11, live in fresh-water. The animal of Paludina is sprinkled all over with bright, golden specks. The Littorinæ, or "Winkles," 12-24, are marine, and frequent the shore among seaweeds. Lacuna, 25-32, belongs to the same family.

Plate XIII., XIV.

Are small genera, various in their characters and habits, but reasonably included in the last family, Littorinidæ.

Plate XV.

The animals of Turritella, 1-3, and Cæcum, 6, 7, are not unlike, although the shells are so different; eyes at the base of the tentacles, a short foot, and horny operculum. The somewhat similar animal of Aporrhais, 4, 5, is brilliantly coloured with gold and red. Cerithium, 8-10, differs from Cerithiopsis, 11-15, more in regard to the animal than the shell; the latter animal has a retractile proboscis, and its operculum is not spiral.

Plate XVI.

Chemnitzia, 1-11, and Truncatella, 12, together with Stylifer, Eulima, and Odostomia, form the family of Pyramidellidæ. Notwithstanding the difference in the shells, the animals are very similar, having a retractile proboscis, and eyes immersed at the base of their tentacles.

The animal of Natica, 13-19, has a lobe on the upper part of the foot, reflected over the shell in front, and another lobe behind. The shells of Laminaria, 23, 24, are completely enveloped in similar lobes.

Plate XVII.

The shells of Odostomia are known by a fold in the inner lip of the aperture.

Plate XVIII.

Two Tritons, 1, 2, are admitted for the first time as British, on what we consider fair evidence, although only two or three specimens have been taken off Guernsey. One of T. nodiferus was incrusted by a truly British Lepralia. Murex, 3, is now familiar as an aquarian, as well as Purpura, 5. A milky secretion found in the head turns purple when exposed, and gives the celebrated purple dye. Buccinum, 7-13, includes the common "Whelk," 8. Fusus Berniciensis, 14, is among the rarest and