Intersex. An individual with characteristics intermediate between those of a male and female.

Intestine. The portion of the alimentary canal posterior to the stomach. Its major functions are the final digestion of food matter from the stomach, the absorption of soluble food matter, the absorption of water, and the production of faces.

Intine. The thin inner coat of a pollen gain, composed of cellulose.

Intrapetiolar. Between the stem and the petiole in plants.

Inulin. Soluble polysaccharide, built of fructose moleculse occurring as stored material in many plants, e.g. members of Composite, dahlia tubers but absent in animals.

Invasion. The entry and colonization of a host by an organism.

Invivo. Within the living organism.

Iris. Structure controlling amount of light admitted to vertebrate eye. it is the coloured part of human eye. It is a thin sheet of tissue, forming a pigmented diaphragm in front of lens with central opening (pupil) through which light passes to retina. Attached all round outer margin to ciliary body (q.v.). Contains rediating muscles which enlarge pupil and a ring of muscles at its free iner which narrows pupil.
Light, stimulating retina and optic nerve, relexly control the size of pupil, narrowing for strong, enlarging fro dim light. Accommodation for near vision also accompanied by narrowing.

Irrigation. Mositening or pouring water over a preparation.

Ischium. Ventral, backward- projecting, part of hip girdle (q.v.) Ischia bear the weight of a sitting primate.

Iso. Denoting equal.

Isobilateral. Having a similar structure in each side, as in the leaf of monocotyledon.