Thats right, I finally got around to doing it. The ref sheet is just basic pictures right now, but I will be putting more info here.

Jaws
The structures that at first appear to be the lower jaw are actually split down the center and open wide, normally used only to hold food win concert with the upper jaw. The true lower law is actually the beak like structure at the back of the throat, which also contains the tongue. The excations teeth are actually outgrowths of their exoskeleton.

Tongue
The excations tongue is around two feet long, and made of the same kind of 'hard' flesh that the inner ears are made from. The tongue has the ability to taste, smell and detect radiation, and is totally prehensile. It is normally clean, but when the excation gets hungry, it secretes a slightly yellow saliva.

Ears
The ears are triangular in cross-section, and inside the contain multiple flat sheets of tissue filled with blood. These structures are used for oxygen exchange, with the slits in the ears closing up during periods of environmental danger, such as in low oxygen, vacuum and sandstorms.

Eyes
The Excation see in red and infrared light, which lets them see the heat signatures of animals while in earths atmosphere. They where unaware of this capability, as in their environment, most animals matched the ambient heat.

Stomach
The excatcion stomach sits in the chest cavity normally. Its a readily expandable sac-like organ, lined with sharp spines that produce the yellow acids. The excation digestive system is efficient but simple, containing nothing but the mouth, throat and stomach.

Blood
Excation have a binary vascular system, with a inner blood that resides in vessels that connect the major organs, and an outer heamolymph that sits between the exoskeleton and internal organs. Both do the job of oxygenation and circulating chemicals, but the inner blood is more efficient.

The inner blood is the source of one of the more unusual defence mechanisms in the excation body, when exposed to atmospheric oxygen, it turns into a neurotoxin, which can kill the excation quite rapidly, in a few minuets.

Exoskeleton
The excation exoskeleton is tough but flexible, with short, soft blue fur covering the outside. In some places there are gaps where a soft conective tissue lays over tendons and muscles to protect them. The exoskeleton is made mostly of keratin.

Endoskeleton
Ridgid and extrmely strong when dealing with compressive forces. Due to the fact that the excation have an exoskeleton, the endoskeleton only preforms a supportive role.

Other organs
Excation have a pair of large heavy organs that sit above the hips that act as a liver, spleen, kidneys and other regulatory organs. It is there organs that are effected by drugs and chemicals, including the hormons that cause them to produce more of the sugar-neutralising chemical.

The excation have a large air store running down their back between two hearts. The air sacs oxygen store is periodically replaced every two hours or so. Do not point it out, its a pretty embarressing for the excation. The store is too alow them to breath when the cant use their normal respiratory organs.