Morphological Structures and Functions:
Over time, all Gastropods have developed a process called torsion (Gillis, 2012). Torsion is a 180º twisting of the visceral mass and occurs in the development stages of the organism (Gillis, 2012). The process of torsion brings the anus and mantle cavity forward so that it is located above the head of the Gastropod (Gillis, 2012). With the anus located above the head, Gastropods quickly learn to refrain from defecating while feeding (Klein, 2012). (See image left)
Gastropods have an open circulatory system
(Hickman et. al., 2012). In open circulatory systems, the blood
(hemolymph) is not only located in the heart, but flows through
tissues under low pressure, through channels and sinuses (Gillis,
2012). (See image right)
Since Neohelix dentifera belongs to the sub-class Pulmonata, it
has diminished its function of the ctenidia (gill) and developed
a lung in its stead (Ghesquiere, 2011). The lung has an opening
to the snail’s environment called the pneumostome which allows
respiration for this little creature (Ghesquiere, 2011).
The foot is the main structure used for
locomotion in snails (Nordseick, 2012). It is also used to
attach to substrates and traverse terrain to locate food (Nordseick,
2012). It can even be used to jump and decrease tangible surface
area of the organism to allow for better regulation of
homeostasis during times of drought (Nordsieck, 2012).
Snails are mainly nocturnal animals that expose
themselves to lower precipitation gradients to allow for less
energy expenditure and to maintain homeostasis (Cain et al.,
2011).
The Neohelix dentifera is
often confused with Tripodopsis albolabris (Burch, 1962). Therefore, it is important to know its morphological
structures and functions. A. Binney’s describes the Neohelix
dentifera's shell as having a dull pale olive color, with a
width approximately 20-35mm containing 5-5
½ whorls. The shell is sculptured with transverse rib-striae
and wrinkles, and spiral incised lines. The shell of this
species is similar to the shell of the Triodopsis
albolabris, but is thinner and much more
depressed. Also, this species contains a tooth (Burch, 1962).
This confusion between Neohelix dentifera and
Triodopsis albolabris is a prime example of sympatric
convergence among distantly related taxa
(Emberton, 2008).
The shell of Neohelix dentifera is used to protect against predators, and serves as a support structure for the snail’s tissues (Gillis, 2012). Shells of most mollusks are made of calcium carbonate (Michigan State, 2002).
Check out how snails feed by clicking on nutrition
Return to Home Page