Homely Mollusk, The

for centuries artists and fiction writers have given the octopus a very bad reputation describing him as a monstrous denisen of the deep but like most of us he can't help his looks and the fact that he looks frightening doesn't necessarily mean that he is belligerant or dangerous however before we get involved with his behavior let's find out something about his biology and ecology octopus live in temperate Waters all over the world these particular specimens were caught by Miami Seaquarium divers in Atlantic Waters off the coast of Florida some of our specimens are caught by squirting a strong saline solution into their layers this is harmless but certainly irritating to the octopus so he leaves his layer and away he goes to our laboratory this is an animal a mollusk one of the class seopa which includes squid cuttlefish and octopus this is octopus vulgaris he is Boneless and invertebrate with a lifespan of 2 to six years he is predatory and carnivorous he eats shrimp crabs and other crustations in adulthood he will have an armspan of 6 to 8 ft all seapods have one outstanding characteristic in common their arms are on their heads the genus octopus has eight arms and they surround his mouth his arms are joined at the base by tissue the inter brachial web this web is used for support in Locomotion as a kind of parachute and also as a place to store food he often catches his food and holds it in his web until he's ready to eat it his arms can be seared from his body but contrary to appearance this is not fatal if it happens there is no bleeding skin curls over the wound and six hours later a clot forms Octopus arms can be regrown but often the new arms don't grow as long as the original ones each arm has an artery and nerve cord along the center of its axis sensory receptors on the arms and suckers Supply the brain with the sense of touch and taste with the most sensitive taste cell on the rims of the suckers each individual sucker can expand and contract independent of all other action suckers are lined with keratin the same basic protein complex of which hair fingernails horns and feathers are made like other catinis tissue the Linings Slough off and Grow Again here we see the castoff Linings drifting in the water what seems to be a stem is the structure of the neuromuscular mechanism that activates the vacuum of the sucker the rims of the suckers with relaxed muscles form a shallow Cup this is a diagram of a non-adhering sucker but when the sucker adheres to an object the muscles contract and the the vacuum mechanism is activated this is a diagram of the adhering position it stays in the adhering position until a signal comes to deactivate the vacuum mechanism and release the sucker contrary to rumor suckers cannot puncture or lacerate human skin this is an octopus face if we can call it that at least it's his head where his brain and eyes are located the octopus eyee remains in a fixed position he must move his head up down or sideways to see his prey is internal organs are contained in his flexible bulbous body sack located behind his head it is called the mantle the mantle has an opening from which the funnel protrudes body wastes from the digestive system are expelled out of the funnel this is the way an octopus gets oxygen seawat is drawn into the mantle cavity through the cavity opening circulates through the mantle passing over the gills where oxygen is extracted and the deoxygenated water is expelled out the funnel the octopus can also use the action of water expulsion for Locomotion by Contracting the mantle musculature suddenly forcing water out of the funnel he is jet propelled through the water backwards looking where he has been not where he is going in spite of his ominous appearance the octopus defense mechanisms are very limited he can hide from his enemies by changing his color and skin texture to blend with his surroundings his suckers can grab and hold or he can spew black ink from his funnel to act as a camouflage while he makes his getaway his ink is fluid of the melanin group related to the color pigmented human hair and skin the ink is not venomous but temporarily paralyzes an enemy's sense of smell as we have said octopi have the ability to change color we'll have him repeat the color change in closeup color change comes from action of the chromatophores tiny pigment cells embedded in the skin each chromatophore contains only one color red Brown predominating on the dorsal or upper side yellow predominating on the ventral or underneath side this is a diagram of a cross-section of octopus tissue on the surface the epidermis below the epidermis the dermis location of chromatophores chromator cells have elastic walls that expand and contract when expanded color granules are visible when they are contracted the color is barely visible beneath the chromatophores also in the dermis are the aridor these cells act as reflectors of light they do not contain the pigment granules held by chromatophores when octopi eggs become larv they are already equipped with about 75 chromatophores note the dramatic color changes in these larv 2 hours old they share this scene with a common pin the skin may change texture as well as color taking on the rough appearance of rocks in the surrounding area normal texture of the skin is wrinkled and loose with wart-like pil through muscular control the octopus can cause these pil to erect to review the octopus is equipped with two distinct external characteristics for camouflage the ability to change color and the ability to change the texture of his skin this fellow lives compatibly with his neighbors if they let him alone within this peaceful community is an exception the green Mor the octopus mortal enemy with sharp hooked teeth and Powerful neck muscles the is notorious as a vicious biter this peaceful scene might continue except the Moray is invading octopus territory the octopus clings to the Rock to keep from being dragged into the Mor's layer that little striped fish is curious but not about to get involved although the octopus has lost several arms that's not a problem he can grow new ones in American Waters the octopus mates during the spring and summer culation is performed by a special arm of the male called the hectus arm it's modified with a Groove and spoon-shaped tip to transfer sperm from inside his funnel into the theme male mantle cavity where he glues the sperm to the interior of her OV ducts at spawning time the female hangs her stringy clusters of eggs in cave likee openings in rocks or other places where she can protect and care for them she's a good mother during the hatching period of 50 days keeping the egg clusters clean by squirting them with water from her funnel but as soon as the eggs hatch into larve mother octopus has no further interest in her Offspring for the first month the larv are plank tonic meaning they are free swimming their location is dependent on whims of the currents of the sea later he will settle to the bottom and begin life as an octopus this two-month-old character is about to take his place in the life cycle we have seen of the much maligned but really gentle and intelligent creature octopus vulgaris the homely mollus for