arachno-, arachn- +
(Greek: spider; the arachnoidea; when used in medicine this Greek element refers to a membrane, veins, or any web-like structure in the body)
Spiders, Spiders Everywhere
Currently, about 30,000 species of spiders have been recognized, although it is certain that many more have yet to be discovered in all parts of the world.
The spiders are known to occupy nearly every terrestrial habitat, from the peaks of the highest mountain ranges into the depth of the largest caves and holes, from damp marshes to dry deserts. Anywhere in fact that they can find other arthropods to provide them with meals.
A spider is popularly thought to be an insect, although it is an arachnid of the order Araneae.2. A computer program that searches the internet for newly accessible information to be added to the index examined by a standard search tool: When Jack bought his new computer, he made sure that it had a spider in order to gather new facts and knowledge for his classes at school.
Spiders are every where in abundance
Currently, about 30,000 species of spiders have been recognized, although it is certain that many more have yet to be discovered from all parts of the world.
Spiders are known to occupy nearly every terrestrial habitat, from the peaks of the highest mountain ranges to the depths of the largest caves and pot-holes; from damp marsh to dry desert, anywhere in fact that they can find other arthropods to provide them with a meal.
Some spend at least part of their lives running around on the surface of the freshwater lakes and ponds and a few of these can dive to safety and survive below the surface of the water for a short time, although only the true water spider, Argyroneta, has perfected this ability to the extent that it is able to live a wholly aquatic existence.
All spiders are carnivorous and feed almost exclusively on prey which they have caught for themselves, although a few species take advantage of food which has been taken by other spiders and one family feeds exclusively on other spiders.
Although many species of spiders have a fairly wide distribution both within and between the continents of the world, the majority tend to be found within a fairly restricted habitat because they are specifically adapted to live in that particular area.
A spider adapted for living in a damp, marshy habitat, for example, would find it impossible to live in the hot, dry conditions that exist within deserts.
In practice, the subarachnoid space is between the arachnoid and the pia mater, the innermost membrane surrounding the central nervous system.
The subarachnoid area normally contains cerebrospinal fluid. A subarachnoid hemorrhage is a bleeding into this space.
The arachnoid is named for its delicate, spider-web-like filaments that extend from its undersurface through the cerebrospinal fluid in the subarachnoid space to the pia mater (delicate and highly vascular membrane immediately covering, or enveloping, the brain and spinal cord).