In poisonous snakes the fangs are developed on

Answer

### Step-by-Step Solution:

1. **Identify the Structure**: In poisonous snakes, the fangs are specialized structures that play a crucial role in their feeding and defense mechanisms.

2. **Determine the Location**: The fangs of poisonous snakes are specifically developed on the maxillary teeth. The maxillary teeth are the teeth located on the upper jaw of the snake.

3. **Understand the Modification**: In these snakes, a few of the maxillary teeth are modified to become fangs. These fangs are not just ordinary teeth; they have specific adaptations that allow them to inject venom into their prey.

4. **Characteristics of Fangs**: The fangs are typically conical in shape, curved, and sharply pointed. This design helps in piercing the skin of the prey and delivering venom effectively.

5. **Regeneration**: An important feature of these fangs is that they can regenerate if they are lost. This is crucial for the survival of the snake, as it relies on its fangs for hunting.

6. **Apertures of Fangs**: The fangs have two important apertures: the intake aperture, which is located at the base of the fang, and the discharge aperture, which is sub-terminal (located near the tip of the fang). These apertures facilitate the entry of venom into the prey.

7. **Positioning**: There is one fang on each side of the maxillary bone, allowing the snake to effectively use both fangs during feeding.

### Final Answer:
In poisonous snakes, the fangs are developed on the maxillary teeth.