Which of the following statement is incorrect w.r.t. class cyclostomata?

Options

A. The members are ectoparasites on some fishes
B. Their body is devoid of scales and paired fins
C. Circulation is of open type
D. They are marihe but migrate for spawning of fresh water

Answer

To determine which statement is incorrect with respect to the class Cyclostomata, we need to analyze each provided statement carefully. Here’s a step-by-step breakdown:

### Step 1: Understand the Class Cyclostomata
Cyclostomata is a class within the subphylum Vertebrata, which includes jawless fish such as lampreys and hagfish. They are characterized by their unique feeding habits and anatomical features.

### Step 2: Review the Statements
We need to evaluate the truthfulness of each statement regarding Cyclostomata.

1. **Members are ectoparasites on some species.**
- This statement is **true**. Many members of Cyclostomata, particularly lampreys, are known to be ectoparasites, feeding on the blood of other fish.

2. **Their body is devoid of scales and paired fins.**
- This statement is also **true**. Cyclostomata lack scales and do not possess paired fins, which are characteristic features of other fish classes.

3. **Circulation is of open type.**
- This statement is **false**. The circulatory system of Cyclostomata is actually closed, which is a significant characteristic of this class.

4. **They are marine but migrate for spawning to freshwater.**
- This statement is **true**. Many species within Cyclostomata are marine but migrate to freshwater for spawning, a behavior known as anadromous migration.

### Step 3: Identify the Incorrect Statement
From the analysis:
- The third statement, "Circulation is of open type," is incorrect because Cyclostomata have a closed circulatory system.

### Conclusion
The incorrect statement regarding the class Cyclostomata is: **"Circulation is of open type."**

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