________are considered as invertebrate chordates.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the name of organisms that are classified as invertebrate chordates.

2. **Identifying the Organisms**: Invertebrate chordates are organisms that possess some characteristics of chordates but do not have a backbone. These organisms are known as protochordates.

3. **Defining Protochordates**: Protochordates are divided into two main groups:
- **Cephalochordates**: In these organisms, the notochord extends from the brain to the tail. An example of a cephalochordate is the lancelet.
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