Martian physiology: The Mantel

Martians are covered by a tough mantle of non-living integument, produced by a ring of tissue on the top of the head and held in the mouth at the bottom of the body. The mouth slowly but continuously pulls in the mantel and eats it, at the same rate as it is produced at the top of the body. The mantel is tough and airtight, formed by millions of ribbon-like filaments with zipper-shaped interlocking edges. Where they are produced at the top of the head, they must be preened and made to lie parallel (see Martian mating and childrearing). Oil is produced from glands in the skin around the origin of the mantel and spread across its surface by action of the tentacles, improving its insulating qualities until the mantel is nearly airtight. The inner side of the mantel is likewise coated in mucus, which seals ruptures in the mantel and makes it more resistant to gross physical damage. Commensal organisms and parasites may often be found living in this lining (see Martian lice, Martian scale, the black dust).
The mantel functions as biological armor against the elements. Kept at a consistently higher temperature, air pressure, and humidity inside than out, it is a cloak not of invisibility to sight, but of invincibility to the harsh cold airlessness of the Martian desert. In this, the Martian’s native environment, pressure differential causes the mantel to swell like a balloon (see sketch above left), but on Earth, the mantel cannot be inflated and hangs loose (see sketch above right, with a Gentleman for size comparison). This causes health problems for the Martian, most notably hyperventilation (as the Martian instinctively gasps, trying to pump air into the chamber) and infection (as bacteria tend to multiply in places where the mantle folds). There are several ways to ameliorate or prevent these issues, used by different Martian factions to suit different lifestyles (see strutting, dreading, tightening, immersing, replacing, shearing).
The mantel is breached in five places. The first is at the top of the head where the mantel ribbons are produced. Mucus and continuous grooming and pleating of the mantel ribbons reduces leakage, and artificial skull caps seals it. Some leakage also occurs at the bottom, or “skirt,” of the mantel, where the greater tentacle clusters push through, and the material enters the mouth. A complex system of valves and chambers has evolved to combat this problem, and is often enhanced further by clothing. (see Martian clothing) The mantel is parted at the top of each eye, and then rejoined at the bottom, creating the distinctively clownlike Martian visage. Mucus seals around the eyes’ lenses prevent air and water leakage, although we are told there is considerable leakage of heat through these orifices. The most profound connection to the outside air is through the hole made by the siphon, or breathing tube. Often erroneously called the “mouth,” this simple V-shaped hole is cut through the mantel integument by teeth on the edge of the siphon through which the Martian may breathe. On Mars, exchange of gasses need take place only once every two hours or so, and for the remainder of the time, the hole is sealed with mucus. On Earth, however, most Martians keep their breathing holes permanently ajar, creating the gasping action remarked upon by so many earthly observers.
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This is a project where I am extending the history begun by the eminent H.G. Wells in War of the Worlds. As far as I know, this creature matches the descriptions he gives in his book. Let me know what you think.

This color picture replaces an earlier black and white sketch. I'm working on a short story based on this concept. More soon.

The original discussion of the idea: ([link])
Map of mars: ([link])
Continents of mars: ([link])
Martian races: ([link])
Martian religions: ([link])
Martian economic blocks: ([link])
A short story written in this universe: [link]

More...maybe, if there's interest