Spot the mistakes in the given statements and correct them,
a) The middle covering of CNS is thin and vascularised and is called Piameter
b) The innermost cover of CNS is a very thin delicate membrane and is closely applied on the outer surface of brain and spinal cord and it is called Arachnoid membrane.

Explanation

Let's analyze the statements and identify the mistakes step by step.

### Step 1: Analyze the first statement
**Given Statement:** The middle covering of CNS is thin and vascularised and is called Piameter.

**Mistake Identification:**
- The term "Piameter" is incorrect.
- The middle covering of the central nervous system (CNS) is not called "Piameter"; it is called the "Arachnoid membrane."
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