Boring sponge is

Options

A. Cliona
B. Spongilla
C. Euspongia
D. Hyalonema

Answer

**Step-by-Step Text Solution:**

1. **Understand the Question**: The question asks about the "boring sponge" and requires identifying which sponge fits this description from the given options.

2. **Evaluate the Options**:
- **Option 1: Cliona** - This is known as the boring sponge. Cliona species are capable of boring into calcium-rich substrates, such as shells, by chemically drilling tiny holes.
- **Option 2: Spongilla** - This is incorrect. Spongilla is a freshwater sponge and does not have the boring capability. Its skeleton is made up of siliceous spicules.
- **Option 3: Euspongia** - This option is also incorrect. Euspongia, commonly known as the "bath sponge," has a skeleton made of spongin fibers, not known for boring into substrates.
- **Option 4: Hylonema** - This option is incorrect as well. Hylonema is known as the "glass rope sponge" and does not exhibit boring behavior.

3. **Conclusion**: Based on the evaluation, the correct answer is **Option 1: Cliona**, as it is the only sponge known for boring into calcium-rich objects.