352 SCYLLiEA. MOLLUSCA. Pneumobkanchiata. 
Gexus ScylLyEA. — T he Scyllceas are oceanic, and 
and which are in consequence supposed to impart a 
are found on floating sea-weed, the slender fronds of 
similar colour to their captors. Dr. Johnston gives 
which thej'^ seize by their furrowed or channeled foot. 
a good description of the Glaucus hexapterygius, 
being by this enabled to obtain a firmer grasp and 
a species from the Mediterranean. “ The body,” he 
greater security. — See Plate 6, fig. 1 {Scyllcea pelagica). 
says, “ glows with a fine cerulean blue colour, which 
Genus Tethys. — T he Telhyses are oceanic, attach- 
deepens in hue towards the ends of the fringes of its 
ing themselves, like the Scyllseas, to floating sea -weed. 
ptero-branchiae ; the centre of the back is of a pearly 
Their broadly expanded head-veil, fringed with cirrlii. 
whiteness, bordered with a line of deep blue ; and the 
gives them a peculiar look. One of them is mentioned 
sides are adorned with an interrupted series of fan-like 
by Dr. Johnston, on the authority of Rapp, to be remark- 
laciniated gills, by aid of which it swims reversed at the 
able, not more for its singular beauty than by its odour. 
surface of the Mediterranean Sea in numerous swarms.” 
which is compared to that of roses. — See Plate 6, fig. 1 
[Tethys leporina). 
In a third series of this groTip (the CerabrancJna of 
Family^ — EOLIDIDA l. 
Gray) the gills, which are placed, like the last, on the 
upper surface of the mantle, are fusiform, papillary. 
The EoUds are generally elegant and beautifully 
simple, or branched. Such are the families Dendro- 
coloured creatures, and are active, constantly moving 
notldce, Procfonotidce, Hervidce, Dotonidm, Glaiicidm, 
tbeir tentacles and extending and contracting their 
Eolididce, Fionidce, and Hermmidce, examples of some 
papillte.— (See Plate 6, figs. 1-4.) They are often to 
of which will be seen in Plate 6. 
be met with swimming on the surface in an inverted 
Genus Glaucus. — T he Glauctises have slender. 
position ; but, generally speaking, they frequent rocks 
cylindrical gills placed in tufts, proceeding symmetri- 
at low water. Their chief food consists of Zoophytes, 
cally from the sides of the body, and supported on broad 
but Alder and Hancock inform us that they have seen 
flattened footstalks. The animals are oceanic in their 
the Flahellina punctata devour other Nudibranchs, and 
habits, are predaceous, and are generally of a blue 
even make a repast upon its own spawn. The spawn 
colour. — See Plate 6, fig. 1 {Glaucus Atlanticus). 
of Eolis papulosa “forms an elegant spiral chain of a 
Dr. George Bennett informs us, in his “Wanderings,” 
milk colour, and several inches long, twisted upon itself 
that they feed greedil}' on the gelatinous Acalephs, 
and constricted at regular intervals, so as to resemble 
Velellae, and Porpitae, animals always of a blue colour. 
a necklace made of bugles.” — [Johnston.) 
Order III. — PNEUMOBRANCHIATA Pulmonata or Pulmonipera). 
The air-breathing Gasteropods, containing the “ Slugs” 
giving the appearance of a tesselated pavement. The 
and “Snails,” are for the most part natives either of the 
greater proportion of these animals are herbivorous. 
land or fresh water, a few only being found in salt 
living upon land plants and vegetables; and in these 
marshes or places near the sea. They are, with very 
the teetli are all similar in form, with broad bases and 
few exceptions, provided with a shell, both in their 
dentate crowns. Some, bowever, are carnivorous, and 
young or larval state, and when fully grown. They 
in these the teeth are slender, and more or less pointed 
have no gills, but breathe the atmosphere or external 
or barbed at the extremity. “ The mode in which the 
air by means of a lung which is in the form of an air 
tongue is used may be seen by placing a Lymnea or 
sac or cavity placed on the front of the back, and litied 
Planorbis in a glass of water, inside which the green 
by a network of vessels. The air is admitted into this 
conferva has begun to grow ; they will be observed 
cavity by an orifice in the side of the animal, which is 
incessantly cleaning off this film. The upper lip, with 
small and valve-like, and can be opened and shut at 
its mandible, is raised ; the lower lip, which is horse- 
pleasure. The young of the air-breathing Molluscs 
shoe shaped, expands, the tongue is protruded and 
undergo no metamorphosis, but when first hatched are 
applied to the surface for an instant, and then with- 
shaped like the parent, and are not furnished with 
drawn ; its teeth glitter like glass paper, and in Lj'mnea 
cephalic fins. They are hermaphrodite animals, the 
it is so flexible that frequently it will catch against 
sexes being united in each individual. They are 
projecting points and be drawn out of shape slightly as 
usually active and well organized, having a distinct head 
it vibrates over the surface.”^ — [Woodward.) The shell 
furnished with teeth, jaws, well-developed eyes, and 
of the Pulmonata is not secreted on the exterior of 
tentacles. They have a broad foot upon which they 
the mantle, as in other Gasteropods (see p. 185). 
creep, and the great majority of them possess a large. 
“Gegenbaur draws attention to the fact that the first 
spiral shell. In this latter respect, however, they differ 
rudiment of the shell in Limax, Clausilia^ and proba- 
considerably — some genera of slugs having only small, 
bly Helix, is not secreted on the exterior of the mantle, 
concealed shells, flat, and partially membranous; other 
as in other Gasteropoda, but is deposited, in the form 
slugs having the shells rudimentary and granular, while 
of calcareous granules, within its substance.” — [Huxley.) 
a few have none at all. The tongue, or lingual mem- 
The “ Slugs ” and “ Snails ” are universally distributed 
brane, is short and very broad, often nearly as wide as 
over the globe, but are of a large size, and more numer- 
long ; and the teeth are very numerous, similar, with 
ous individually in warm, moist, intei tropical countries, 
broad bases, and invariabl}' arranged in transverse rows. 
and are especially abundant in large, well wooded 
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