1. Shell:
- Snails: Snails have a spiral or conical external shell that provides protection for their soft body. The shell is made of calcium carbonate and is secreted by the snail's mantle.
- Slugs: Slugs, on the other hand, lack an external shell. Their bodies are soft, elongated, and covered with a protective layer of mucus.
2. Body Structure:
- Snails: Snails have a distinct head, foot, and visceral mass. The head contains sensory organs such as eyes, tentacles, and mouth. The foot is a muscular structure that enables snails to move by crawling. The visceral mass contains internal organs.
- Slugs: Slugs also have a head, foot, and visceral mass, but their body is streamlined and elongated without the protective shell.
3. Respiration:
- Snails: Most snails have a specialized organ called a lung for respiration. They breathe by inhaling air into the lung through an opening called the pneumostome and expelling carbon dioxide.
- Slugs: Slugs have a different respiratory system compared to snails. They breathe through a thin, vascularized layer of skin, allowing them to absorb oxygen directly from the air.
4. Habitat:
- Snails: Snails can be found in various habitats, including both terrestrial and aquatic environments. Some species live on land, while others are adapted to live in freshwater or marine environments.
- Slugs: Slugs are predominantly terrestrial, meaning they live on land. They are commonly found in moist environments, such as forests, gardens, and damp areas under rocks or logs.
5. Feeding Behavior:
- Snails: Most snails are herbivorous and feed on plant matter, including leaves, algae, and fruits. Some snail species can be detritivores, feeding on decaying plant matter or organic debris.
- Slugs: Slugs are also primarily herbivorous and feed on plant material. However, some slugs are omnivorous, occasionally consuming small insects or other invertebrates.
6. Mucus:
- Snails: Snails produce mucus to help them move over surfaces, reduce water loss, and protect themselves from external factors.
- Slugs: Slugs rely more heavily on mucus compared to snails. They secrete a copious amount of mucus to facilitate their movement and protect their delicate bodies from drying out.
These differences in shell structure, body form, respiration, habitat preferences, feeding behavior, and mucus production contribute to the distinction between snails and slugs. While they share some similarities as members of the Gastropods, their adaptations and lifestyles set them apart as distinct groups within the diverse gastropod family.