.:ABOUT SNAILS:.

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About Snails

CONTENTS:
-Types of Snails
-Anatomy and Physiology of the Snail -The characteristics of the snail:

The Shell
The Body
Other Organs
Mating
Egg-hatching
The Cover – Operculum

Helix-Pomatia

Types of Snails

Snails are classified into a large group of animals of the phylum Mollusk (lat.Mollusca). There are over a hundred thousand molluscs. Four thousand of these form the class of snails (Gastropods), of the subclass Pulmonata. The snails we are interested in are the helicid snails (the family Helicidae) because they have the external shell spiral (Helix) shaped.
Out of these numerous types of snails, three to four hundred types live on the territory of Europe. For our future education of snail breeding, it is not necessary to know how many types there are in our country. It is important to distinguish edible species, and furthermore to distinguish those the market is interested in.
At about thirty species are used as food, and only a few of them have conquered the market. The species interesting for our conditions are: Helix aspersa (also known as the French "petit gris", "small grey snail" or "La Zigrinata") and Helix pomatia (also called the "Roman snail","apple snail","lunar","La Vignaiola", the German "Weinbergschnecke", the French "escargot de Bourgogne" or "Burgundy snail" or "gros blanc").
The most interesting species for farm raising is the vineyard snail (lat. HELIX POMATIA), also known as the garden or white snail.

Different Varieties of Snails ->

The Vineyard Snail
This species can be found all over our country. It is often found in vineyards, gardens, orchards or near rivers and streams. It is fond of chalky (calcium-rich) and relatively dry soil.

Anatomy and Physiology of the Snail

Life and habits of this mollusk may seem insignificant at first sight. Yet, they have aroused the interest of many scientists who have studied its life and anatomy thus giving us the opportunity to learn about their discoveries.
The snail passes through some critical periods during a year. In the spring, the snail comes out of the shell in which it has spent the winter and it starts its search for food to restore strength lost during winter months. Then comes the mating period characterized by restless and nervous search for a mate. Fortnight after mating, the snail looks for the place to lay eggs which makes it completely exhausted. Snails lose substantial weight by laying eggs.
During the summer snails revive their strength by eating larger quantities of food.

In the autumn the snail starts its search for a shelter and forms the firm cover – operculum so as to be protected during the winter.

A breeder must know completely snail’s life phases in order to provide optimal raising conditions on time. In this way, one will avoid unnecessary losses and achieve successful production.

The characteristics of the SNAIL

1. The Shell
This is one of the greatest works of geometry in nature. It consists of chalky material and one specific organic substance – CONHIOLIN – that is the basic substance for shell formation. Numerous shapes of shell help us easily differentiate between many species.

2. The Body
There have been considerable changes and disorders regarding internal organs and spiral coiling of the shell that are not found at other animals.
The head is in the front part of the body, and is easily noticeable. It is consisted of the mouth and four tentacles of which the upper pair is longer.
The foot, protruding from the shell, allows movement and sticking of the snail to the ground. The bottom part of the foot contains many glands that secrete slime thus creating visible silvery trace. Thanks to that the snail can slide over a razor’s edge without hurting itself. Its movements are slow but strong. The lower part of the foot is made of strong muscles.

3.Other Organs
Digestive organs, pneumostome, nerve system, blood vessels and reproductive organs make the complete anatomy of the snail.

4. Mating
Snails are mollusk – hermaphrodites and incomplete animals. Although they have both male and female reproductive organs, they do not have the ability of self-reproduction. Mating occurs from March to June. Sometimes there is a second mating in the early autumn.
After mating, it looks for a place to lay eggs that is safe from accumulation of other snails since it can be the case that one snail throws out eggs of another one. Having found convenient place, it starts to make a hole using its strong foot. The snail puts its head into the hole or may crawl in until only the top of the shell is visible. It deposits eggs in intervals of few minutes from the genital opening just behind the head. Eggs, bound by a thin slimy thread, fall into the hole slowly. It takes the snail 1 to 2 days to lay all eggs.
Helix Pomatia snails lay 40 to 60 eggs (according to some authors even 100). Eggs are white, round, soft and jelly-like. They measure 3 to 4mm in diameter.

5. Egg-hatching
Incubation period lasts for 30 days. The hatchlings break eggshell and come out. They immediately need a lot of calcium so they eat broken eggshells. They can move and feed themselves; have small, pearly, one-spiral shaped shell. They develop very fast and can become four times larger within the first month. They are capable for mating in the second year and their life expectancy is 7 to 10 years.

6. The Cover – Operculum
The cover is formed in the autumn, when the temperature falls bellow 10°C and snails prepare for their winter rest. Driven by their instinct, they search for a shelter so as to be protected from weather changes, snow, frost, high humidity or sudden rises of temperature.
Having found an adequate shelter (by crawling into ground 5 to 10 cm), they place themselves with the gills turned upward to allow easier oxygen exchange. They clean their digestive organs from food left-overs.

To do this they retreat into shells, put on soap-like membrane and start emptying the dirt collected in the centre of this thin tissue. After this, they are prepared for the winter phase and they start forming the real cover – operculum – which hardens in contact with air and becomes whitish because of the containing calcium.
Preparations for this phase last for 4 to 5 days, and the operculum is formed within a minute. The cover – operculum - shows snail’s condition and health. If it is placed to the shell’s edge and bubbled, the snail is healthy and can survive the winter. Otherwise, if the operculum is pulled into the shell, we can not expect the snail to survive.