The external anatomy of a slug The external anatomy of a slug includes the following: Tentacles Like other pulmonate land gastropods, the majority of land slugs have two pairs of 'feelers' or tentacles on their head. The upper pair is light sensing and has eyespots at the ends, while the lower pair provides the sense of smell.
Note the oral tentacles otfoot tentacles fteye erhinophores rand cerata c. This species has cnidosacs cn at the cerata tips.
The body forms of nudibranchs vary a great deal, but because they are opisthobranchs, unlike most other gastropods, they are apparently bilaterally symmetrical externally but not internally because they have undergone secondary detorsion. In all nudibranchs, the male and female sexual openings are on the right side of the body, reflecting their asymmetrical origins.
They lack a mantle cavity. Some species have venomous appendages cerata on their sides, which deter predators.
Many also have a simple gut and a mouth with Behavior of sea slugs radula. The adult form is without a shell or operculum in shelled gastropods, the operculum is a bony or horny plate that can cover the opening of the shell when the body is withdrawn.
In most species is a swimming veliger larva with a coiled shell which is shed at metamorphosis when the larva transforms into the adult form. Some species have direct development and the shell is shed before the animal emerges from the egg mass. Nudibranchs have cephalic head tentacles, which are sensitive to touch, taste, and smell.
Club-shaped rhinophores detect odors. Nudibranchs Nembrotha kubaryana eating Clavelina tunicate colonies In the course of their evolution, nudibranchs have lost their shells, while developing alternative defense mechanisms.
Some species evolved an external anatomy with textures and colors that mimicked surrounding sessile invertebrate animals often their prey sponges or soft corals to avoid predators camouflage. Other nudibranchs, as seen especially well on chromodoridshave an intensely bright and contrasting color pattern that makes them especially conspicuous in their surroundings.
Nudibranch molluscs are the most commonly cited examples of aposematism in marine ecosystems, but the evidence for this has been contested,  mostly because few examples of mimicry are seen among species, many species are nocturnal or cryptic, and bright colors at the red end of the spectrum are rapidly attenuated as a function of water depth.
For example, the Spanish dancer nudibranch genus Hexabranchusamong the largest of tropical marine slugs, potently chemically defended, and brilliantly red and white, is nocturnal and has no known mimics.
Once further into the organ, the cells are assimilated by intestinal protuberances and brought to specific placements on the creature's hind body. Nudibranchs can protect themselves from the hydrozoids and their nematocysts; the specific mechanism is yet unknown, but special cells with large vacuoles probably play an important role.
Similarly, some nudibranchs can also take in plant cells symbiotic algae from soft corals and reuse these to make food for themselves. The related group of sacoglossan sea slugs feed on algae and retain just the chloroplasts for their own photosynthetic use, a process known as kleptoplasty.
Nudibranchs use a variety of chemical defenses to aid in protection,  but it is not necessary for the strategy to be lethal to be effective; in fact, good arguments exist that chemical defenses should evolve to be distasteful rather than toxic.
Furthermore, nudibranchs contain a mixture of sponge chemicals when they are in the presence of multiple food sources, as well as change defense chemicals with a concurrent change in diet.
Certain species are able to produce their own chemicals de novo without dietary influence. Evidence for the different methods of chemical production comes with the characteristic uniformity of chemical composition across drastically different environments and geographic locations found throughout de novo production species compared to the wide variety of dietary and environmentally dependent chemical composition in sequestering species.
Apparent production of sound[ edit ] InPhilip Henry Gosse reported observations by "Professor Grant" possibly Robert Edmond Grant that two species of nudibranchs emit sounds that are audible to humans.
Facelina annulicornis ], and Tritonia arborescens [i. Dendronotus frondosus ], certainly produce audible sounds. Professor Grant, who first observed the interesting fact in some specimens of the latter which he was keeping in an aquarium, says of the sounds, that 'they resemble very much the clink of a steel wire on the side of the jar, one stroke only been given at a time, and repeated at intervals of a minute or two; when placed in a large basin of water the sound is much obscured, and is like that of a watch, one stroke being repeated, as before, at intervals.
The sound is longest and most often repeated when the Tritonia are lively and moving about, and is not heard when they are cold and without any motion; in the dark I have not observed any light emitted at the time of the stroke; no globule of air escapes to the surface of the water, nor is any ripple produced on the surface at the instant of the stroke; the sound, when in a glass vessel, is mellow and distinct.
In a small apartment they are audible at the distance of twelve feet. The sounds obviously proceed from the mouth of the animal; and at the instant of the stroke, we observe the lips suddenly separate, as if to allow the water to rush into a small vacuum formed within.
As these animals are hermaphrodites, requiring mutual impregnation, the sounds may possibly be a means of communication between them, or, if they are of an electric nature, they may be the means of defending from foreign enemies one of the most delicate, defenceless, and beautiful Gasteropods that inhabit the deep.Springs, USA.
The slug had previously been identified as Elysia patina based on a recent description, but later evidence suggested this was incorrect.
Furthermore, despite the evidence found for the slug’s photosynthetic capabilities, little was known of its ecological relationships and behavior. They are carnivores that slowly ply their range grazing on algae, sponges, anemones, corals, barnacles, and even other nudibranchs.
To identify prey, they have two highly sensitive tentacles, called rhinophores, located on top of their heads. The brightly colored sea slugs, or nudibranchs, live and feed on hydroid colonies It's uncertain how widespread this behavior might be but it's hoped this and future research could contribute.
Slug, or land slug, is a common name for any apparently shell-less terrestrial gastropod kaja-net.com word slug is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced shell, or only a small internal shell, particularly sea slugs and semislugs (this is in contrast to the common name snail, which applies to gastropods that have a coiled shell Phylum: Mollusca.
Behavior of Sea Slugs specifically for you. for only $/page. Order Now. First we notice that when the UN is higher in the sky the slugs move further away, and when it is lower, or not in the sky the slugs get closer together.
This could be a result of the slugs trying to regulate their body heat. As the sun gets higher, the warmer the.
Other memory researchers say that the changes in sea slug behavior don't constitute true memory, but rather a simple increase in sensitivity to stimuli. Even if these results can be replicated, other memory researchers say that the changes in sea slug behavior don't constitute true memory, but rather a simple increase in sensitivity to stimuli.